| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
METABOLISM AND NUTRITION |
Departamento de Producción Animal, Universidad Politécnica de Madrid, Ciudad Universitaria, Madrid 28040, Spain
3 Corresponding author: gonzalo.gmateos{at}upm.es
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
0.001). In addition, feeding rice increased the pH of gizzard digesta (P 0.001) and reduced the relative weight (RW) of most digestive organs. Heat processing had little effect on the growth or size of digestive organs but improved the TTAR of most nutrients in the corn diets. Fiber inclusion improved the TTAR of most nutrients, BW gain (P 0.01), and feed conversion (P 0.001) from 1 to 21 d of age. In addition, fiber inclusion increased the RW of the gizzard (P 0.001), ceca (P 0.05), and digestive tract (P 0.01) and reduced digesta pH (P 0.001) and the length of the small intestine (P 0.05). The effects of hulls on RW of the gizzard and on the TTAR were more pronounced for the rice diets than for the corn diets. We concluded that rice can be used successfully in broiler diets and that heat processing of the cereal does not have any beneficial effect on broiler performance. The inclusion of moderate amounts of fiber in low-fiber diets might improve chick performance at early ages by reducing gizzard pH and improving the utilization of nutrients. Therefore, young broiler chicks might require a minimal amount of fiber in the diet.
Key Words: rice • corn • heat processing • fiber source • chick
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Rice is the most abundant cereal in the world and part of the production is destined to animal feeding. Rice feeding of piglets is a common practice in many countries because its inclusion in the diet increases feed intake and improves growth (Mateos et al., 2006). However, rice inclusion in diets for broilers has not been studied in detail. Rice might be a good source of energy in posthatch diets for chicks because of its high starch content, reduced proportion of amylose in the starch, and low content of nonstarch polysaccharides and other antinutritional factors. Heat processing of the cereal is commonly practiced in piglet diets to improve nutrient digestibility and productive performance (Medel et al., 2004; Mateos et al., 2006), but the information available on the influence of HP on chick growth is scarce and contradictory (Vuki
Vranje
and Wenk, 1995; Moritz et al., 2005).
The influence of fiber content of the diet on voluntary feed intake and total tract apparent retention (TTAR) of nutrients in broilers is the subject of debate (Moran, 2006). Janssen and Carré (1985) indicated that the fibrous components of feedstuffs negatively affect chick growth; consequently, they recommended a reduction of the fiber content of diets for young chicks. However, some researchers have indicated that an adequate type and amount of fiber might improve adaptation of the GIT of poultry to current productive systems and reduce digestive disturbances under a scenario without in-feed antibiotics (Mateos et al., 2002; Montagne et al., 2003). Hetland et al. (2005) observed that birds had an appetite for fiber and that when the diet did not provide a minimal amount of this nutrient, they would consume increased amounts of litter. Therefore, chicks might have a requirement for a minimal amount of fiber. The aim of this research was to evaluate the influence of HP of the cereal and inclusion of fiber in the diet on the productive performance and digestive traits of broilers fed low-fiber diets based on either corn or rice from 1 to 21 d of age.
|
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Cereals, Fiber Sources, and Diets
Two batches of yellow corn or polished broken rice (Japonica variety; 80% Senia and 20% Tainato cultivars) were obtained from a commercial supplier (Essasa, Cabezón de Pisuerga, Valladolid, Spain) and split into 2 fractions. The first fraction of both cereals was ground through a hammer mill (2.5-mm screen, Bühler AG, Vzwill, Switzerland) and used in the manufacture of the feeds. The second fraction of corn was steam-cooked (Amandus Kahl, Reinbek, Germany) for 60 min at 104 ± 3°C, cooled, dried, flaked through riffled rolls, and then ground before being included in the diet. A similar procedure was used for the second portion of rice, but in this case, the cereal was cooked for 45 min at 90 ± 3°C. Soy hulls (SH) and oat hulls (OH) were obtained from the same commercial supplier, ground through a hammer mill (2-mm screen, Retsch Model Z-I, Stuttgart, Germany), and included as such in the corresponding experimental diets. The composition and the mean particle size (MPS) of the test cereals and fiber sources are shown in Table 1
.
|
). In the remaining experimental diets, 3% of either OH or SH was included at the expenses (wt/wt) of sepiolite. The composition of the experimental diets is shown in Table 3.
|
|
The 2 experiments were conducted using the same husbandry, diets, and experimental design. One-day-old straight-run broiler chicks (Cobb 500) were obtained from a commercial hatchery (Cobb España, Alcalá de Henares, Spain) and allocated to a windowless, environmentally controlled room. Chicks were housed in groups of 16 in battery cages (Jamesway type, 1 x 0.9 m2, Avícola Grau S.A., Madrid, Spain) provided with wire flooring and equipped with 2 drinkers and 1 lineal feeder. Room temperature was kept at 33°C during the first 3 days of the trial and was then reduced gradually according to age until reaching 24°C at 21 d. The chicks were kept on a 23 h/d light program and had free access to feed and water throughout the trial. In experiment 1, a total of 1,152 chicks (initial BW of 44.4 ± 3.8 g) were divided into 6 blocks by weight and housed in 72 cages. In experiment 2, a total of 576 chicks (initial BW of 39.2 ± 3.1 g) were divided into 3 blocks by weight and housed in 36 cages. In both trials, diets were randomly assigned within each block.
The trials were conducted as randomized complete block designs with 12 dietary treatments arranged factorially, with 2 cereals (corn and rice), 2 HP treatments of the cereal (raw and cooked), and 3 fiber sources (control, 3% OH, and 3% SH). All diets were fed in mash form.
Analytical Evaluation of Ingredients, Feeds, and Feces
For determination of the distribution and MPS of ground cereals, hulls, and experimental diets, 3 subsamples of 50 g were sieved using a Filtra 200 shaker (Filtra S.A., Barcelona, Spain) provided with 7 sieves ranging from 2,500 to 40 µm. The method outlined by the American Society of Agriculture Engineers (ASAE, 1995) was used.
Feeds and feces were analyzed for moisture by the oven-drying method (930.15), total ash by a muffle furnace (942.05), nitrogen by the Dumas method (968.06) using Leco equipment (model FP-528, Leco Corporation, St. Joseph, MI), and ether extract (EE) by Soxhlet fat analysis after 3 N HCl acid hydrolysis (920.39) as described by the Association of Official Analytical Chemists (AOAC, 2000). Gross energy was measured with an adiabatic bomb calorimeter (model 356, Parr Instrument Company, Moline, IL) and acid-insoluble ash was analyzed using the technique described by Van Keulen and Young (1977) with modifications. Briefly, feed and excreta samples were analyzed sequentially for DM, ash, and acid-insoluble ash with the same beaker, and ashing was performed at 600°C for 12 h rather than of 450°C for 6 h. Starch contents of ingredients and feeds were measured by the 
-amylase glucosidase method (996.11) and crude fiber by sequential extraction with diluted acid and alkali (962.09; AOAC, 2000). Neutral detergent fiber (NDF) and acid detergent fiber were determined sequentially as described by Van Soest et al. (1991) and expressed on an ash-free basis.
Productive Performance (Experiments 1 and 2)
Body weights of chicks and feed consumption were determined by cage at 0, 4, 8, 14, and 21 d of age, and BW gain (BWG), average daily feed intake (ADFI), and feed to gain ratio (F:G) were determined by period and globally. Feed intake was adjusted for mortality. Birds that died during the experiment were weighed, and their BWG was included in calculations of F:G. Feed wastage was recorded by replicate for each period.
Digestive Traits (Experiment 1)
At 14 and 21 d of age, 2 or 4 chicks per cage, respectively, were randomly selected, weighed individually, and killed by cervical dislocation. The pH of gizzard contents was measured at both ages, and the remaining digestive traits were measured only at 21 d. The digestive tract with contents was removed aseptically and weighed, and the proventriculus, gizzard, liver, small intestine (SI), and ceca were excised, cleaned, dried with desiccant paper, and measured. The weight of the empty organs was expressed relative to live BW (RW), whereas the weight of the gizzard digesta was expressed relative to full gizzard weight. In addition, the lengths of the SI and the ceca were determined and expressed relative to empty BW (without the digestive tract). Gizzard digesta was collected in 2 birds at 14 and 21 d of age and homogenized in a 50-mL beaker, and pH was measured in duplicate using a digital pH meter (Crisson Instruments S.A., Barcelona, Spain). Moisture of the gizzard digesta was determined by oven-drying at 60°C for 72 h. At 21 d of age, the jejunum (defined as the region from the pancreas tail to Meckel’s diverticulum) of the remaining 2 birds was dissected aseptically and the digesta contents were collected as described by Lázaro et al. (2004). The viscosity (in centipoise) of a 0.5-mL aliquot obtained from the supernatant solution was determined with a Brookfield digital viscometer (model DV III, Brookfield Engineering Laboratories Inc., Stoughton, MA) at 24°C. Each sample was read twice, and the average value of the 2 birds was used for statistical analysis.
TTAR (Experiment 2)
At 18 d of age, representative samples of excreta produced during the previous 24 h were collected by replicate, homogenized, oven-dried (60°C for 72 h), and ground with a hammer mill (1-mm screen, Retsch ModelI). The TTAR of DM, organic matter, soluble ash, EE, and nitrogen, and the AMEn of the diets were estimated by the indigestible marker method using 2 N HCl insoluble ash as an indicator. Celite (acid-washed diatomaceous earth, Celite Corporation, Lompar, CA) was added at 1% to all diets as an additional acid-insoluble ash source. The AMEn content of the experimental diets was calculated as described by Lázaro et al. (2003).
Statistical Analysis
All data set were analyzed for normal distribution using the NORMAL option of the UNIVARIATE procedure, and for homogeneity of variances using the HOVTEST option of the GLM procedure of SAS (SAS Institute, 1990). Productive performance data were analyzed as a randomized complete block design and main effects (type of cereal, HP, and fiber inclusion) and their interactions were studied. The results in tables are reported as least squares means. All differences were considered significant at P 0.05. Preplanned orthogonal comparisons were used to determine the effects of hull inclusion (control vs. fiber) and type of hulls (OH vs. SH). For pH data, age was included as a fourth factor. The experimental unit was the cage for all traits studied.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
) and diets (Table 3) were close to the expected values. Mean particle size was greater for raw corn than for raw rice (548 vs. 438 µm, respectively) and for SH than for OH (582 vs. 467 µm, respectively). Consequently, MPS was greater for the corn diets than for the rice diets and increased with hull inclusion. The MPS of the diets ranged from 579 µm for HP corn with 3% OH to 456 µm for HP rice without hulls (Table 3). Productive Performance
Mortality was very low (2.5% in experiment 1 and 1.0% in experiment 2) and was not related to treatment (data not shown). Most of the mortality occurred (>80%) during the first week of the trial.
Effect of Cereal.
From 1 to 4 d of age, broilers fed the corn diets ate more feed (17.1 vs. 16.6 g/d; P 0.05) and grew faster (13.4 vs. 13.1 g/d; P 0.01) than did broilers fed the rice diets, but F:G was not affected (Table 4). In this period, broilers fed rice wasted more feed than did broilers fed corn (2.6 vs. 2.2 g/d; P 0.05; data not shown), but no differences were found thereafter. From 4 to 21 d of age, chicks fed corn had poorer F:G than did broilers fed rice (1.24 vs. 1.19, P 0.001 from 4 to 8 d; 1.32 vs. 1.26, P 0.001 from 8 to 14 d; and 1.44 vs. 1.39, P 0.05 from 14 to 21 d). Consequently, from 1 to 21 d of age, broilers fed corn had poorer F:G (1.37 vs. 1.32; P 0.001) but similar BWG and ADFI than did broilers fed rice (Table 4).
|
0.001) and impaired F:G (1.29 vs. 1.24; P 0.01) without affecting ADFI. Also in this period, broilers fed raw cereals wasted more feed than did broilers fed HP cereals (2.7 vs. 2.2 g/d; P 0.01; data not shown) but no differences were detected after this age. A cereal x HP interaction was observed for F:G and BWG at early ages and for ADFI at the end of the experiment. From 1 to 4 d and from 8 to 14 d of age, HP of the cereal impaired F:G in chicks fed corn but not in chicks fed rice (P 0.001). In addition, HP reduced BWG from 1 to 4 d of age in broilers fed corn but had no effect on broilers fed rice (P 0.001). From 1 to 21 d of age, HP increased ADFI in birds fed corn but reduced it in birds fed rice (P 0.05).
Effect of Fiber.
Hull inclusion consistently improved F:G of chicks. From 1 to 4 d of age, the inclusion of hulls reduced ADFI (16.6 vs. 17.2 g; P 0.05) and improved F:G (1.25 vs. 1.30; P 0.01) but had no effect on BWG. Also in this period, broilers fed the hull-containing diets wasted more feed than did broilers fed the control diets (2.6 vs. 2.2 g/d, P 0.05; data no shown) but no effects were observed thereafter. From 4 to 14 d of age, hull inclusion improved F:G (P 0.05) without affecting BWG or ADFI. From 14 to 21 d of age, chicks fed hulls had higher BWG (49.7 vs. 46.0 g/d; P 0.001) and ADFI (69.4 vs. 66.1 g; P 0.05) and better F:G (1.40 vs. 1.44; P 0.05) than did chicks fed the control diets. Consequently, at the end of the experiment, the inclusion of hulls improved BWG (33.4 vs. 31.7 g/d; P 0.01) and F:G (1.33 vs. 1.37; P 0.001) without affecting ADFI. No significant differences between OH and SH were detected for any of the productive traits studied.
Digestive Traits
Effect of Age.
The pH of gizzard digesta was significantly increased as the bird aged (2.95 vs. 3.09 at 14 and 21 d of age, respectively; P 0.01). The increase was greater (P 0.05) for chicks fed rice (3.00 vs. 3.23) than for chicks fed corn (2.91 vs. 2.94; Table 5).
|
0.001). Fresh gizzard contents were greater (32.0 vs. 21.2%; P 0.001) and had more moisture (66.8 vs. 64.2%; P 0.05) in corn-fed birds than in rice-fed birds (Table 5). Jejunum viscosity was not affected by type of cereal (3.44 vs. 3.56 cP for corn-fed and rice-fed chicks, respectively). Chicks fed corn had a larger digestive tract (P 0.001), proventriculus (P 0.01), gizzard (P 0.001), and ceca (P 0.05) than did chicks fed rice, but liver size and SI and ceca length were not affected (Table 6).
|
0.001). A cereal x HP interaction was observed for the moisture content of the gizzard; HP of corn increased the moisture content of the gizzard more than did HP of rice (P 0.05). In addition, HP of corn reduced the relative length of the SI more than did HP of rice (P 0.05). The RW of the digestive tract (P 0.01) and proventriculus (P 0.001) also were increased with HP of rice, but no effects were observed with HP of corn.
Effect of Fiber.
Inclusion of hulls reduced the pH of gizzard digesta (3.18 vs. 2.94; P 0.001), an effect that was more pronounced (P 0.001) for chicks fed rice (3.40 vs. 2.97) than for chicks fed corn (2.96 vs. 2.91; Table 5). The influence of hull inclusion on gizzard traits depended on the fiber source and cereal used. For example, hulls increased the fresh contents of the gizzard (P 0.001) and SH increased the moisture of gizzard contents (P 0.05) in chicks fed rice, but not in chicks fed corn. Chicks fed hulls had a heavier digestive tract (P 0.01), gizzard (P 0.001), and ceca (P 0.05) and a shorter SI (P 0.05) than did chicks fed the control diets (Table 6). Soy hull inclusion, but not OH inclusion, increased (P 0.05) the RW of the proventriculus, whereas the opposite effect was found for the RW of the gizzard (P 0.01).
TTAR
Effect of Cereal.
The TTAR of DM, organic matter, and EE (P 0.001), of soluble ash (P 0.01), and of nitrogen (P 0.05); and the AMEn of the diet (P 0.001) were higher for rice-based diets than for corn-based diets (Table 7).
|
0.001).
Effect of Fiber.
The inclusion of hulls improved the TTAR of DM, soluble ash, and EE (P 0.001) and the AMEn content of the diet (2,974 vs. 3,040 kcal/kg; P 0.001). A cereal x fiber interaction was observed on the TTAR of many nutrients; the beneficial effects of hulls on TTAR were more evident in the rice-based diets than in the corn-based diets. In addition, the beneficial effect of hull inclusion on the AMEn of the rice diet was more pronounced with OH than with SH (P 0.01).
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
In the current research, F:G from 1 to 21 d of age was improved by 3.6% when corn was substituted (wt/wt) for rice, but BWG and ADFI were not affected. Probably the AMEn value used in the current study for rice and corn (3,360 and 3,260 kcal of AME/kg, respectively; Fundación Española para el Desarrollo de la Nutrición Animal, 2003) underestimated the real energy contribution of rice to the broiler diets.
From 1 to 4 d of age, inclusion of rice reduced the ADFI. The reason is unknown but might be related to differences in the texture of feeds. Shelton et al. (2003) observed that chicks fed a rice-casein diet from 8 to 20 d of age had lower ADFI and BWG than did chicks fed a practical corn-soybean meal diet. In addition, Panigrahi et al. (1992) observed that ADFI and BWG were lower for chicks fed rice diets than for chicks fed corn diets offered as mash, but that the differences almost disappeared when the diets were pelleted. In the current experiment, MPS was smaller for rice diets than for corn diets, and broilers fed rice wasted more feed than did broilers fed corn from 1 to 4 d of age, which might indicate that the texture of the rice diets was not adequate for chicks of this age. However, no differences in feed wastage were observed after 4 d of age, suggesting that the chicks adapted quickly to the texture of the feeds.
Heat processing of the cereal above 90°C is not used to any extent in practical feeding of poultry because of the cost and lack of a consistent response. In our experiment, HP did not affect broiler performance from 1 to 21 d of age and, in fact, impaired BWG and F:G from 1 to 4 d of age. These data disagree with the report of Fancher et al. (1996) indicating that expansion at 90°C of a corn-soybean meal diet improved broiler performance and that of Douglas et al. (1991) indicating that micronization at 150°C of similar types of diets improved productivity from 1 to 21 d of age. Gracia et al. (2003) observed that HP of barley (steam-cooked at 99 ± 2°C for 50 min) improved BWG in broilers from 1 to 8 d of age, but not at 21 d. In fact, in that research F:G from 1 to 21 d of age was reduced by 5% when barley was cooked. In addition, Vuki Vranje and Wenk (1995) observed a reduction in broiler productivity from 7 to 21 d of age when the cereal was extruded. The reasons for the discrepancies among authors are unknown but might be related, at least in part, to differences in the conditions applied during the thermal process and to the type of cereal used. For example, Niu et al. (2003) indicated that broiler productivity was improved when wheat was micronized at 90 or 105°C. However, when the temperature was above 120°C, productivity was reduced.
Traditionally, it has been recommended that the fiber content of diets for young birds be reduced to improve the ADFI (Janssen and Carré, 1985), nutrient digestibility (Jørgensen et al., 1996), and productive performance (Sklan et al., 2003). However, recent reports with young pigs have shown that diets very low in fiber impair nutrient digestibility and growth (Mateos et al., 2006). Hetland and Svihus (2001) indicated that the inclusion of 4% OH in the diet increased ADFI without affecting BWG in broilers from 7 to 21 d of age. In the current research, inclusion of either 3% OH or 3% SH improved F:G at all periods and improved BWG from 1 to 21 d of age, suggesting that inclusion of moderate amounts of fiber in prestarter feeds might be beneficial for poultry. In this respect, Hetland et al. (2005) observed that laying hens fed diets low in fiber exhibited a marked preference for ingesting wood shavings, paper, and feathers, indicating the need for structural components to compensate for the lack of fiber in the diet.
Digestive Traits
In the present study, the pH of gizzard digesta increased with age in chicks fed rice, but not in chicks fed corn. Nir et al. (1995) found that the pH of gizzard digesta increased from 2.68 at 21 d of age to 3.16 at 40 d of age and that the observed increase in pH was higher when the cereal was finely milled. Probably the effects of factors such as the crude fiber content and MPS of the diet on the pH of the proventriculus and gizzard depend on the age of the birds.
Birds fed corn had heavier digestive tracts, with a larger gizzard that had greater digesta contents and lower pH, than birds fed rice, and this effect might be related to the higher fiber content and MPS of the corn diets. Our data agreed with those of Rama Rao et al. (2000), who observed heavier gizzards in hens fed corn than in hens fed rice. In addition, Nir et al. (1994) and Dahlke et al. (2003) observed that gizzard weight and gizzard contents increased and pH of the gizzard digesta decreased when the MPS of the diet was increased. Probably the reduction of gizzard weight observed in chicks fed rice, as compared with chicks fed corn, was due to less mechanical stimulation associated with less digesta contents in the gizzard.
Inclusion of hulls in the diet reduced the pH of gizzard digesta and increased ash solubility, suggesting that the secretion of hydrochloric acid was increased. Duke (1986) indicated that the presence of feed in the gizzard induces secretion of hydrochloric acid in the proventriculus via mechanoreceptors. An increase in dietary fiber might also increase the production of saliva, gastric juices, and pepsin, as has been demonstrated in pigs (Mosenthin et al., 1999). Because of their high content of insoluble fiber, OH and SH are difficult to grind; therefore, it is likely that considerable amounts of hulls remain in the gizzard for longer periods than do regular particles such as those from corn or rice (Hetland et al., 2005). To our knowledge, no published research has compared the effects of different fiber sources on gizzard pH. In fact, in the current trial the gizzard contents were greater in chicks fed hulls than in chicks fed the control diets, indicating that fiber was retained longer in this organ. Hetland and Svihus (2001) also found that inclusion of 4% OH increased the fresh contents of the gizzard in chicks. The gizzard regulates the passing of digesta to the SI; coarse particles are selectively retained until a critical size is reached (Hetland et al., 2005), whereas liquids and soluble material pass to the duodenum, although they might return to the gizzard via gastroduodenal reflux (Duke, 1986).
It is well known that increasing the fiber content of the diet increases the size of the GIT in broilers (Jørgensen et al., 1996; Hetland and Svihus, 2001), but the effects depend on the section considered (Moran, 2006). In the current trial, feeding hulls increased the size of the GIT, gizzard, and ceca and shortened the length of the SI, but the magnitude of the effects differed with the fiber source used. The main physicochemical characteristics of dietary fiber with nutritional significance are viscosity and hydration properties, which influence solubility, water holding capacity (WHC), and swelling capacity (Bach Knudsen, 2001). Insoluble fiber particles may incorporate water into their matrix and swell to a variable extent during their passage through the GIT, resulting in a bulkier digesta. Therefore, enlargement of the GIT in chicks fed hulls might be a consequence of physical distension caused by the swelling of the hulls and the concomitant increase in the bulk of the digesta. Oat hulls and SH are sources of insoluble fiber, but OH are more lignified than SH (Bach Knudsen, 2001). Our data on the moisture of gizzard digesta suggested that the WHC of the digesta was higher in chicks fed SH than in chicks fed OH; therefore, SH might have swelled more than OH, causing a larger proventriculus.
The inclusion of SH affected the size of the proventriculus of chicks fed rice, but not of chicks fed corn. In addition, OH increased the gizzard weight, an effect that was more pronounced for the rice diets than for the corn diets, suggesting that the mechanical strength of hulls interacted with the texture of the cereal. Hetland et al. (2005) found that the gizzard weight and gizzard contents of laying hens with access to wood shavings increased when they were fed a wheat diet (10.7% NDF), but not when they were fed an oat diet (16.4% NDF). Hetland and Svihus (2001) showed that the increase in gizzard weight because of fiber inclusion was greater with coarse OH than with fine OH. Our results suggested that the effects of fiber (either SH or OH) on gizzard characteristics depended on their WHC and resistance to grinding. Probably OH produced more mechanical stimulation on the gizzard than did SH.
In the present study, the length of the SI was reduced by hull inclusion only in the rice diets. The reason for this observation is unknown, but a reduction of the length and weight of the SI has been observed in chicks fed diets with antibiotics (Miles et al., 2006) or diets supplemented with enzymes (Lázaro et al., 2004). In addition, Rogel et al. (1987) observed that inclusion of 10% OH decreased the weight and length of the SI. Similarly, Jørgensen et al. (1996) found that chicks fed oat bran had a shorter SI than did chicks fed the control diet. Miles et al. (2006) attributed the reduction in length of the SI to the thinning of the intestinal wall associated with control of the growth of certain microorganisms by antibiotic feeding. In our research, the reduction in length of the SI of chicks fed OH was associated with a marked accumulation of gizzard contents, acidification of the gizzard digesta, and enlargement of the gizzard. There is evidence that dietary fiber may protect the GIT against enteric infections in diverse species (Montagne et al., 2003; Hedemann et al., 2006). In fact, Mateos et al. (2006) observed that inclusion of OH in the diet tended to reduce the incidence of diarrhea in piglets. A longer retention time of digesta in the gizzard might reduce the risk of microbial infections through longer exposure of feedborne microorganisms to hydrochloric acid. Therefore, the shortening of the SI, together with the improvement in F:G observed in chicks fed hulls might be due to an improvement in gut health.
TTAR
Diets based on rice were more digestible than diets based on corn, in agreement with previous research (Panigrahi et al., 1992; Jadhao et al., 1999). Rice grain has more starch and less fiber and a lower moisture content than corn. In addition, rice starch has a smaller granule size (3 to 8 µm), a lower amylose content, and less nonstarch polysaccharides than does corn starch (Tester et al., 2006). Therefore, a better utilization of nutrients for rice than for corn should be expected, because the digestion process in the GIT is easier with rice.
Heat processing increased the TTAR of nutrients in the corn diet but decreased the TTAR in the rice diet, suggesting that the impact of HP on digestibility depended on the type of cereal used. The reason for the interaction is not known, but HP might disrupt the lipid-amylose complexes and the bond between starch and the protein matrix in the corn grain, increasing nutrient availability (Plavnik and Sklan, 1995; Svihus et al., 2005). For raw rice, Vicente et al. (2007) indicated that starch digestibility is already high; therefore, no further improvement in digestibility should be expected because of HP. On the other hand, most of the EE in the corn diets was encapsulated inside the grain, whereas it was present as free oil in the rice diets. Therefore, it is likely that HP benefited the release and digestibility of fat in the corn diets more than in the rice diets. Studies with piglets (Songqiao et al., 2006; Mateos et al., 2007) showing that HP of corn improves fat and energy utilization confirmed our observations in broilers. However, severe HP for a prolonged time may increase the formation of amylose-lipid complexes, Maillard compounds, and resistant starch (Anker-Nilssen et al., 2006). The data in the current experiment suggest that the processing conditions applied to the cereal were probably adequate for corn but were excessive for rice.
In the current trial the inclusion of additional fiber consistently improved the TTAR of nutrients in chicks fed the rice diets, but few effects were detected in chicks fed the corn diets. In addition, the beneficial effects of hulls were more noticeable with OH inclusion than with SH inclusion. The data indicated that young chicks might have a minimal requirement for fiber in the diet and that the amount required varies depending on the type of fiber. This hypothesis is supported by the finding of Rogel et al. (1987) that the inclusion of fiber sources in broiler diets increased the ileal digestibility of starch. Diets rich in fiber remain in the upper GIT longer and might be digested more completely because of increased peristalsis and production of hydrochloric acid and other digestive enzymes. Hetland et al. (2003) observed that OH inclusion increased amylase activity and bile salt concentration in the chyme of broilers. Hedemann et al. (2006) demonstrated that piglets fed highly insoluble fiber diets have increased mucosal enzyme activity as compared with control pigs fed pectin-containing diets. Our results on gizzard digesta pH and the TTAR of nutrients suggest that gizzard activity has an important role in nutrient utilization.
In conclusion, rice is an ingredient of choice in post-hatch diets for broilers, and HP of the cereal might improve the utilization of nutrients in very young chicks fed corn diets. The data also indicate that young chicks might have a minimal requirement for fiber in the diet. Therefore, we recommend the use of rice and the inclusion of a minimal amount of fiber (>1.5% crude fiber) in diets for young chicks. More studies are needed to improve our knowledge of the influence of HP of cereals on the growth of chicks.
|
ACKNOWLEDGMENTS |
|---|
|
FOOTNOTES |
|---|
2 Current address: Universidad Autónoma de Tlaxcala, Av. Universi-dad 1, Tlaxcala, C. P. 90000, México.
Received for publication December 14, 2006. Accepted for publication April 16, 2007.
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Anker-Nilssen, K., E. M. Foergestad, S. Sahlstrøm, and A. K. Uhlen. 2006. Interaction between barley cultivars and growth temperature on starch degradation properties measured in vitro. Anim. Feed Sci. Technol. 130:3–22.
AOAC (Association of Official Analytical Chemists). 2000. Official Methods of Analysis. 17th ed. AOAC, Gaithersburg, MD.
Bach Knudsen, K. E. 2001. The nutritional significance of "dietary fibre" analysis. Anim. Feed Sci. Technol. 90:3–20.
Boletín Oficial del Estado. 2005. Real Decreto 1201/2005 sobre protección de los animales utilizados para experimentación y otros fines científicos. BOE 252:34367–34391.
Dahlke, F., A. M. L. Ribeiro, A. M. Kessler, A. R. Lima, and A. Maiorka. 2003. Effects of corn particle size and physical form of the diet on the gastrointestinal structures of broilers. Braz. J. Poult. Sci. 5:61–67.
Douglas, J. H., T. W. Sullivan, R. Abdul-Kadir, and J. H. Rupnow. 1991. Influence of infrared (micronization) treatment on the nutritional value of corn and low- and high-tannin sorghum. Poult. Sci. 70:1534–1539.[Web of Science]
Duke, G. E. 1986. Alimentary canal: Secretions and digestion, special digestion functions and absorption. Pages 289–302 in Avian Physiology. P. D. Sturkie, ed. Springer-Verlag, New York, NY.
Fancher, B., I. D. Rollins, and B. Trimbee. 1996. Feed processing using the annular gap expander and its impact on poultry performance. J. Appl. Poult. Res. 5:386–394.
Fundación Española para el Desarrollo de la Nutrición Animal. 2003. Normas FEDNA para la formulación de piensos compuestos. C. de Blas, G. G. Mateos, and P. G. Rebollar, ed. Fund. Esp. Desarro. Nutr. Anim., Madrid, Spain.
Gracia, M. I., M. A. Latorre, M. García, R. Lázaro, and G. G. Mateos. 2003. Heat processing of barley and enzyme supplementation of diets for broilers. Poult. Sci. 82:1281–1291.
Hedemann, M. S., M. Eskildsen, H. N. Laerke, C. Pedersen, J. E. Lindberg, P. Laurinen, and K. E. Bach-Knudsen. 2006. Intestinal morphology and enzymatic activity in newly weaned pigs fed contrasting fiber concentrations and fiber properties. J. Anim. Sci. 84:1375–1386.
Hetland, H., and B. Svihus. 2001. Effect of oat hulls on performance, gut capacity and feed passage time in broiler chickens. Br. Poult. Sci. 42:354–361.[Web of Science][Medline]
Hetland, H., B. Svihus, and M. Choct. 2005. Role of insoluble fiber on gizzard activity in layers. J. Appl. Poult. Res. 14:38–46.
Hetland, H., B. Svihus, and Å. Krogdalhl. 2003. Effects of oat hulls and wood shaving on digestion in broilers and layers fed diets based on whole or ground wheat. Br. Poult. Sci. 44:275–282.[Web of Science][Medline]
Jadhao, S. B., C. M. Tiwari, and M. Y. Khan. 1999. Efficiency of utilization of energy from maize- and broken rice-based diets in old White Leghorn and Rhode Island Red laying hens. Br. Poult. Sci. 40:275–283.[Web of Science][Medline]
Janssen, W. M. M. A., and B. Carré. 1985. Influence of fibre on digestibility of poultry feeds. Pages 71–88 in Recent Advances in Animal Nutrition. W. Haresign and D. J. A. Cole, ed. Butterworths, London, UK.
Jørgensen, H., X. Zhao, K. E. B. Knudsen, and B. O. Eggum. 1996. The influence of dietary fibre source and level on the development of the gastrointestinal tract, digestibility and energy metabolism in broiler chickens. Br. J. Nutr. 75:379–395.[Web of Science][Medline]
Lázaro, R., M. A. Latorre, P. Medel, M. Gracia, and G. G. Mateos. 2004. Feeding regimen and enzyme supplementation to rye-based diets for broilers. Poult. Sci. 83:153–160.
Lázaro, R., M. García, M. J. Araníbar, and G. G. Mateos. 2003. Effect of enzyme addition to wheat-, barley-, and rye-based diets on nutrient digestibility and performance of laying hens. Br. Poult. Sci. 44:256–265.[Web of Science][Medline]
Mateos, G. G., R. Lázaro, and M. Gracia. 2002. The feasibility of using nutritional modifications to replace drugs in poultry feeds. J. Appl. Poult. Res. 11:437–452.
Mateos, G. G., F. Martín, M. A. Latorre, B. Vicente, and R. Lázaro. 2006. Inclusion of oat hulls in diets for young pigs based on cooked maize or cooked rice. Anim. Sci. 82:57–63.
Mateos, G. G., E. López, M. A. Latorre, B. Vicente, and R. P. Lázaro. 2007. The effect of inclusion of oat hulls in piglet diets based on raw or cooked rice and maize. Anim. Feed Sci. Technol. 135: 100–112.
Medel, P., M. A. Latorre, C. de Blas, R. Lázaro, and G. G. Mateos. 2004. Heat processing of cereals in mash or pellet diets for young pigs. Anim. Feed Sci. Technol. 113:127–140.
Miles, R. D., G. D. Butcher, P. R. Henry, and R. C. Littell. 2006. Effect of antibiotic growth promoters on broiler performance, intestinal growth parameters, and quantitative morphology. Poult. Sci. 85:476–485.
Montagne, L., J. R. Pluske, and D. J. Hampson. 2003. A review of interactions between dietary fibre and the intestinal mucosa, and their consequences on digestive health in young non-ruminant animals. Anim. Feed Sci. Technol. 108:95–117.
Moran, E. T. 2006. Anatomy, microbes, and fiber: Small versus large intestine. J. Appl. Poult. Res. 15:154–160.
Moritz, J. S., A. S. Parsons, N. P. Buchanan, W. B. Calvalcanti, K. R. Cramer, and R. S. Beyer. 2005. Effect of gelatinizing dietary starch through feed processing on zero to three week broiler performance and metabolism. J. Appl. Poult. Res. 14:47–54.
Mosenthin, R., E. Hambrecht, and W. C. Sauer. 1999. Utilization of different fibres in piglets feeds. Pages 227–256 in Recent Advances in Animal Nutrition. P. C. Garnsworthy and J. Wiseman, ed. Nottingham Univ. Press, UK.
NRC (National Research Council). 1994. Nutrient Requirements of Poultry. 9th rev. ed. Natl. Acad. Press, Washington, DC.
Niu, Z. Y., H. L. Classen, and T. A. Scott. 2003. Effects of micronization, tempering, and flaking on the chemical characteristics of wheat and its feeding value for broiler chicks. Can. J. Anim. Sci. 83:113–121.
Nir, I., R. Hillel, I. Ptichi, and G. Shefet. 1995. Effect of grain particle size on performance. 3. Grinding pelleting interactions. Poult. Sci. 74:771–783.[Web of Science][Medline]
Nir, I., R. Hillel, G. Shefet, and Z. Nitsan. 1994. Effect of grain particle size on performance. 2. Grain texture interactions. Poult. Sci. 73:781–791.[Web of Science][Medline]
Noy, Y., and D. Sklan. 2002. Nutrient use in chicks during the first week posthatch. Poult. Sci. 81:391–399.
Noy, Y., and D. Sklan. 1999. Different types of early feeding and performance in chicks and poults. J. Appl. Poult. Res. 8:16–24.
Panigrahi, S., S. Phillips, V. E. Plumb, and A. J. Watson. 1992. Evaluation of the nutritive value of yellow rice in rats and broiler chicks. Br. J. Nutr. 68:573–582.[Web of Science][Medline]
Plavnik, I., and D. Sklan. 1995. Nutritional effects of expansion and short time extrusion on feeds for broilers. Anim. Feed Sci. Technol. 55:247–251.
Rama Rao, S. V., M. R. Reddy, N. K. Prarharaj, and G. Shyam Sunder. 2000. Laying performance of broiler breeder chickens fed various millets or broken rice as source of energy at a constant nutrient intake. Trop. Anim. Health Prod. 32:329–338.[Web of Science][Medline]
Rogel, A. M., D. Balnave, W. L. Bryden, and E. F. Annison. 1987. Improvement of raw potato starch digestion in chicks by feeding oat hulls and other fibrous feedstuffs. Aust. J. Agric. Res. 38:629–637.[Web of Science]
SAS Institute. 1990. SAS STATs User’s Guide: Version 6. 4th ed. SAS Inst. Inc., Cary, NC.
Shelton, J. L., I. Mavromichalis, R. L. Payne, L. L. Southern, and D. H. Baker. 2003. Growth performance of different breed crosses of chicks fed diets with different protein and energy sources. Poult. Sci. 82:272–278.
Sklan, D., A. Smirnov, and I. Plavnik. 2003. The effect of dietary fibre on the small intestines and apparent digestion in the turkey. Br. Poult. Sci. 44:735–740.[Web of Science][Medline]
Songqiao, L. V., D. Li, J. Xiang, Y. Ma, D. Huang, and J. Li. 2006. Effects of extrusion of corn on growth performance, nutrient digestibility and short-chain fatty acid profile in the hindgut of weaned piglets. Arch. Anim. Nut. 60:170–179.
Svihus, B., A. K. Uhlen, and O. M. Herstad. 2005. Effect of starch granule structure, associated components and processing on nutritive value of cereal starch: A review. Anim. Feed Sci. Technol. 122:303–320.
Tester, R. F., X. Qi, and J. Karkalus. 2006. Hydrolysis of native starches with amylases. Anim. Feed Sci. Technol. 130:39–54.
Van Keulen, J., and B. A. Young. 1977. Evaluation of acid-insoluble ash as a natural marker in ruminant digestibility studies. J. Anim. Sci. 44:282–287.
Van Soest, P. J., J. B. Robertson, and A. Lewis. 1991. Methods for dietary fiber, neutral detergent fiber, and nonstarch poly-saccharides in relation to animal nutrition. J. Dairy Sci. 74:3583–3597.[Abstract]
Vicente, B., R. Lázaro, D. G. Valencia, M. P. Serrano, and G. G. Mateos. 2007. The effects of rice feeding in substitution of corn and the degree of starch gelatinization of rice on digestibility of dietary components and productive performance of young pigs. J. Anim. Sci. doi.:10.2527/jas.2006-697.
Vuki Vranje, M., and C. Wenk. 1995. The influence of extruded vs. untreated barley in the feed, with and without dietary enzyme supplement on broiler performance. Anim. Feed Sci. Technol. 54:21–32.
This article has been cited by other articles:
|
|
 |
|
  N. Parera, R. P. Lazaro, M. P. Serrano, D. G. Valencia, and G. G. Mateos Influence of the inclusion of cooked cereals and pea starch in diets based on soy or pea protein concentrate on nutrient digestibility and performance of young pigs J Anim Sci, February 1, 2010; 88(2): 671 - 679. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. Jimenez-Moreno, J. M. Gonzalez-Alvarado, A. Gonzalez-Serrano, R. Lazaro, and G. G. Mateos Effect of dietary fiber and fat on performance and digestive traits of broilers from one to twenty-one days of age Poult. Sci., December 1, 2009; 88(12): 2562 - 2574. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Jimenez-Moreno, J. M. Gonzalez-Alvarado, R. Lazaro, and G. G. Mateos Effects of type of cereal, heat processing of the cereal, and fiber inclusion in the diet on gizzard pH and nutrient utilization in broilers at different ages Poult. Sci., September 1, 2009; 88(9): 1925 - 1933. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Frikha, H. M. Safaa, M. P. Serrano, X. Arbe, and G. G. Mateos Influence of the main cereal and feed form of the diet on performance and digestive tract traits of brown-egg laying pullets Poult. Sci., May 1, 2009; 88(5): 994 - 1002. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. M. Safaa, E. Jimenez-Moreno, D. G. Valencia, M. Frikha, M. P. Serrano, and G. G. Mateos Effect of main cereal of the diet and particle size of the cereal on productive performance and egg quality of brown egg-laying hens in early phase of production Poult. Sci., March 1, 2009; 88(3): 608 - 614. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. de Coca-Sinova, D. G. Valencia, E. Jimenez-Moreno, R. Lazaro, and G. G. Mateos Apparent Ileal Digestibility of Energy, Nitrogen, and Amino Acids of Soybean Meals of Different Origin in Broilers Poult. Sci., December 1, 2008; 87(12): 2613 - 2623. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Gonzalez-Alvarado, E. Jimenez-Moreno, D. G. Valencia, R. Lazaro, and G. G. Mateos Effects of Fiber Source and Heat Processing of the Cereal on the Development and pH of the Gastrointestinal Tract of Broilers Fed Diets Based on Corn or Rice Poult. Sci., September 1, 2008; 87(9): 1779 - 1795. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Garcia, R. Lazaro, M. A. Latorre, M. I. Gracia, and G. G. Mateos Influence of Enzyme Supplementation and Heat Processing of Barley on Digestive Traits and Productive Performance of Broilers Poult. Sci., May 1, 2008; 87(5): 940 - 948. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
