Effects of whole wheat feeding on the development of the digestive tract of broiler chickens

Effect of Different Feed Particle Size on Gastrointestinal Tract Morphology, Ileal Digesta Viscosity, and Blood Biochemical Parameters as Markers of Health Status in Broiler Chickens

The study is focused on how the physical structure of the feed affects the health status of broiler chickens. The aim of this study was to evaluate the influence of feed particle size in broiler diets on gastrointestinal tract morphology, digesta viscosity, and blood biochemical parameters. A total of 90 one-day-old male Ross 308 broiler chickens were randomly divided into three different experimental groups (with five replicates per pen), with 6 birds per cage. The first experimental group (Coarse) was fed with the coarsest particle size, with feed with a geometric mean diameter (GMD) of 1111.26 µm, the next group (Medium) was fed with a less coarse feed size of GMD 959.89 µm, and the last group (Fine) was fed a diet with a fine feed particle size of GMD 730.48 µm. The use of coarse feed particle size in the diet had a positive effect on the gizzard weight and small intestinal villi height and crypt depth, which increased the surface area intended for digesting nutrients. The use of finely ground particles in the feed increased the level of gamma-glutamyl transferase and at the same time, decreased the level of urea, which could indicate adverse changes in the liver.

Free-Choice Feeding of Whole Grains Improves Meat Quality and Intestinal Development of Pigeon Squabs Compared with Complete Pelleted Feed

Effects of different feeding strategies on meat quality and intestinal development in pigeon squabs were investigated. 120 pairs of pigeons with two squabs each were assigned to five groups (four free-choice feeding systems and one complete feeding system): T1 (corn, pea, wheat, and pelleted feed), T2 (corn, wheat, and pelleted feed), T3 (corn, pea, and pelleted feed), T4 (corn and pelleted feed), and T5 (complete pelleted feed). Compared with T5, the diet in T4 made the breast meat redder and more yellow (p < 0.05). T2 and T4 resulted in an enhanced total superoxide dismutase activity of meat. Breast muscle in T1 and T2 was determined to have higher contents of nonessential amino acids, glycine, alanine, and glutamic acid (p < 0.05). The contents of the essential amino acids, lysine, threonine, valine, histidine, and arginine were also higher in T1 (p < 0.05). Villus height, surface area, and alkaline phosphatase activity of the duodenum and jejunum in T2 were the highest among the treatments (p < 0.05). In conclusion, free-choice feeding system can improve the meat quality and intestinal development of pigeon squabs, but which combination method of whole grains to use in the production depends on the feeding purpose.

Transcriptome-wide analysis reveals gluten-induced suppression of small intestine development in young chickens

Wheat gluten is an increasingly common ingredient in poultry diets but its impact on the small intestine in chicken is not fully understood. This study aimed to identify effects of high-gluten diets on chicken small intestines and the variation of their associated transcriptional responses by age. A total of 120 broilers (Ross Strain) were used to perform two animal experiments consisting of two gluten inclusion levels (0% or 25%) by bird’s age (1 week or 4 weeks). Transcriptomics and histochemical techniques were employed to study the effect of gluten on their duodenal mucosa using randomly selected 12 broilers (3 chicks per group). A reduction in feed intake and body weight gain was found in the broilers fed a high-gluten containing diet at both ages. Histochemical photomicrographs showed a reduced villus height to crypt depth ratio in the duodenum of gluten-fed broilers at 1 week. We found mainly a significant effect on the gene expression of duodenal mucosa in gluten-fed broilers at 1 week (289 differentially expressed genes [DEGs]). Pathway analyses revealed that the significant DEGs were mainly involved in ribosome, oxidative phosphorylation, and peroxisome proliferator-activated receptor (PPAR) signaling pathways. These pathways are involved in ribosome protein biogenesis, oxidative phosphorylation and fatty acid metabolism, respectively. Our results suggest a pattern of differential gene expression in these pathways that can be linked to chronic inflammation, suppression of cell proliferation, cell cycle arrest and apoptosis. And via such a mode of action, high-gluten inclusion levels in poultry diets could lead to the observed retardation of villi development in the duodenal mucosa of young broiler chicken.

Lambs fed diets containing by-product from coconut processing: histomorphometry characteristics in the digestive and renal systems

This study aimed to evaluate the histological characteristics in the digestive and renal systems of lambs fed diets containing coconut by-product (CB). A total of 35 male lambs with an initial weight of 16.9 ± 2.93 kg were distributed in a completely randomized design with five levels of CB in the diet (0; 4.8; 9.6; 14.4 and 19.2% in total dry matter). Samples of the liver, kidney, rumen, and intestine were histomorphometrically evaluated, and the data were submitted to regression analysis, at a 5% error probability. The inclusion of CB linearly decreased the dry matter intake and caused a quadratic effect for the height of ruminal papillae, absorption area, epithelium thickness, as well as for average daily gain. The inclusion of CB linearly increased the mucous layer and reduced the submucosal layer, as well as promoted a decrease in goblet cells in the small intestine. The inclusion of CB did not influence hepatic glycogen; additionally, the histopathological examination did not reveal liver damage or congestion, vacuolization, and necrosis of the renal tissue. Therefore, our results indicate that CB can be included in lambs diet up to the level of 7.2% without causing changes in the histomorphometry characteristics of the gastrointestinal tract and changes in liver and kidney tissue that compromise animal performance.

nThe effect of partial replacement of milled finisher feed with wheat grains on the production efficiency and meat quality in broiler chickens

The study's aim was to assess the production efficiency, evaluate the carcass and meat quality of chickens fed with wheat grains. 200 Ross 308 chickens were divided into 4 groups (5 replicates with 10 birds in each): control (C) and experimental groups, including W50, where the finisher feed was diluted with wheat grain in 50%, W25–25%, and W10–10%. The production efficiency and chemical composition of the feed were analyzed. After 42 d of rearing, 10 birds from each group were selected, and the tissue composition, pH, color, water-holding capacity, drip loss, the chemical composition of meat, and the apparent protein digestibility, bone, and jejunum strength were investigated. It was proved that ground feed had an unfavorable effect on the body weight (BW) in all groups. Wheat decreased the protein level (P < 0.001) and digestibility (P < 0.001). The body weight gain (BWG) in group W50 was lower than in groups C and W10 (P = 0.009), however, this had no effect on the final feed conversion ratio (FCR) (P = 0.146). Finisher feed costs were reduced in groups W50, W25 compared to group C (P < 0.001). The European Production Efficiency Factor and the European Broiler Index in groups W10 and W25 were similar to group C, whereas in W50 they were reduced (P = 0.035; 0.034). No negative effect on carcass traits was shown in groups W10 and W25, however, 50% feed replacement was unbeneficial compared to group C. Pectoral muscles from the experimental groups were characterized by higher lightness (P < 0.001). In group W10 femur bones' strength and in group W25 tibia bones' strength was higher than in group W50 (P = 0.014; 0.006). Jejunum tensile strength was higher in group W25 than in W10 (P = 0.002). The nutritional strategies based on the dilution of the feed with wheat grain could be applied at the level of 10/25%, but 50% had a negative effect.

Influence of grain physical characteristics on functional value of poultry feed

The purpose of this investigation was to analyze the scientific literature concerning the influence of grain physical characteristics on functional value of poultry feed. The review considers the role of grain feed particle size and its shape in ensuring optimal development and functioning of digestive tract and increasing productivity of birds. The results showed that compared to the feeding with smaller particles, the use of coarse feed increased stomach weight in broilers, enhanced enzymatic degradation of feed in digestive tract and improved nutrient bioavailability. The study found that increase in the level of coarse corn in the diet increased the number of Lactobacillus spp. and Bifidobacteria spp. beneficial bacteria in digestive tract. Meanwhile, number of opportunistic pathogenic microorganisms decreased. In birds which were given granular feed we found insufficient development of stomach, mainly due to the lack of mechanical stimulation. We assume that in order to improve stomach function and health of birds, it is necessary to apply a source of dietary fiber to their diet. The results of studies suggest that adding 2-3% of insoluble source of fiber to the routine diets of young chickens based on high-protein soy flour and corn can improve their digestive tract development and growth characteristics.

Lignocellulose as an insoluble fiber source in poultry nutrition: a review

Extensive research in recent years into the use of various fiber sources in poultry nutrition has led to the perception that dietary fiber is more than a simple diet diluent. Several studies showed that the feeding of insoluble fiber sources such as oat hulls, sunflower hulls or wood shavings may affect digestive physiology and function improving chickens health and growth performance. In this context, the effect of lignocellulose as an insoluble dietary fiber source is increasingly being investigated. Lignocellulose is a component of plant cell walls and consists mainly of the insoluble carbohydrate polymers cellulose and hemicelluloses as well as the phenolic polymer lignin. Lignocellulose is chemically and physicochemically different from other insoluble fiber sources and thus possibly has different effects on poultry compared to traditional fiber sources. Several studies investigated the effect of dietary lignocellulose on growth performance, nutrient digestibility, gastrointestinal tract development and intestinal microbiota in broilers and laying hens. Studies differed in terms of feed formulation and lignocellulose inclusion level as well as products of different suppliers were used. The results obtained are inconsistent; beneficial, indifferent or detrimental effects of feeding lignocellulose were observed, so that a final assessment of lignocellulose as a “novel” insoluble fiber source is difficult. This review article summarizes the results of studies in connection with the feeding of lignocellulose to poultry, compares them with those that have used other insoluble fiber sources and illuminates the possible mechanisms of action.

A Preliminary Study of Chemically Preserved and High-Moisture Whole Maize (Zea mays L.) Usage in Pekin Duck Nutrition: Effect on Growth Performance and Selected Internal Organ Traits

Simple Summary

Harvested maize grains characterized by high moisture require the use of additional preservation processes to secure against the microbiota. The most commonly used practice is heat-drying, which is energy- and cost-consuming, as well as environmentally unfriendly. Thus, there is a need to omit these harmful techniques and evaluate the usage of wet maize in animal nutrition. The present study aimed to investigate the effect of the chemically preserved, high-moisture whole maize grain addition in Pekin duck nutrition on their growth performance and selected internal organ and gastrointestinal tract measurements and digesta pH values. The results of the experiment clearly showed that there is a possibility to partially replace commonly used heat-dry maize with the preserved whole-grain form without an adverse effect on the birds’ performances and selected organ morphometrical parameters. However, due to surprising changes in the pH values in the gizzard and caeca, further investigations, including microbiota analyses, are recommended.

Abstract

This study aimed to investigate the effect of chemically preserved, high-moisture whole maize grain addition in Pekin duck diets on their growth performance and selected internal organ and gastrointestinal tract measurements and digesta pH values. A total of 300 29-d-old male Pekin ducks were randomly distributed into three dietary treatments using five replicate pens per group and 20 birds per pen. The following treatment groups were applied: CON—basal diet, 5HM—5% of high-moisture, chemically preserved whole maize (HM) inclusion, and 10HM—10% of HM addition. The experiment lasted 21 d. The implementation of 5HM or 10HM did not affect (p > 0.05) the growth performance parameters, selected internal organ weights, and the gastrointestinal tract segment weights and lengths. However, significant changes in terms of the gizzard (p = 0.005), ileum (p = 0.030), and caecal (p < 0.001) digesta pH were observed, especially in the case of the 10HM group, which exhibited the greatest increase in pH in the gizzard and caecal digesta and decrease in the ileal digesta pH. The implementation of whole wet maize may be used in waterfowl diets from 29 d of age. Additionally, chemical preservation can efficiently reduce the cost of maize preparation in duck nutrition.

Effect of hybrid rice varieties on growth and development of broilers and ducks

Three experiments (Exp. 1, n = 144 broilers [Ross × Ross]; Exp. 2, n = 118 mallard ducklings [Anas platyrhynchos]; and Exp. 3, n = 75 mature mallard ducks) were conducted to determine the effects of 3 levels of unmilled hybrid rice on growth performance and organ and gastrointestinal tract development. The dietary treatments were 1) corn-soybean meal (basal), 2) basal + 5% hybrid rice, and 3) basal + 10% hybrid rice for Exp. 1 to 3, respectively. One bird from each pen in Exp. 1 (n = 24) and all the birds in Exp. 2 (n = 118) and Exp. 3 (n = 75) were randomly selected and euthanized to determine linear measurements and organ and gastrointestinal tract weight. In Exp. 1 and 2, birds fed 10% rice experienced slower growth (P < 0.05) than birds fed the basal diet. In Exp. 3, the addition of rice did not affect growth performance. Rice addition did not affect organ length or weight (P > 0.05) in Exp. 1. However, birds fed 5% rice had significantly increased (P < 0.05) pancreas, ileum, and jejunum weights in Exp. 2, and 10% rice significantly increased (P < 0.05) liver weight in Exp. 3. The addition of 10% unmilled rice to broiler and duck diets may reduce growth performance.

Effects of graded levels of microbial fermented or enzymatically treated dried brewer's grains on growth, digestive and nutrient transporter genes expression and cost effectiveness in broiler chickens

BACKGROUND

Poultry feed consists mainly of conventional grains and protein supplements, however, using treated unconventional agro-industrial by-products as replacements of corn soybean-based diet can minimize production costs and improve productivity. Therefore, in this study, the effects of fermented or enzymatically treated dried brewer grains (DBG) on growth, expression of digestive enzymes and nutrient transporters genes and the profitability of the rations were evaluated. A total of 1600 one-day-old Ross 308 broiler chicks were randomly distributed in 2 × 4 factorial arrangement (eight treatments with ten replicates, 20 birds/replicate). Experimental diets included two controls; negative control (basal corn-soybean diet; NC) and positive control (basal corn-soybean diet with exogenous enzymes; PC), and six diets in which basal diet was replaced by three levels of fermented DBG (FDBG; 5, 10 or 15%), or enzyme-treated DBG (DBG 5, 10 or 15%+Enz), for 38 days.

RESULTS

The results described that feeding FDBG (three levels) or DBG5%+Enz improved (P < 0.05) BW gain and feed efficiency of broilers. Also, feeding FDBG10% yielded the best improvement in weight gain (10%), compared to NC group. Increasing the inclusion levels of DBG either fermented or enzymatically treated up-regulated (p < 0.01) expression of digestive-genes in proventriculus (PGC and PGA5, range 1.4-1.8 fold), pancreas (AMY2A, PNLIP, CELA1, and CCK; range 1.2-2.3 fold) and duodenum (CAT1, CAT2, GLUT1, GLUT2, LAT1, Pep1; range 1.3-3 fold) when compared to NC group. Feeding treated DBG significantly increased (p < 0.05, range 4.5-13.6%) gizzard relative weight compared to NC and PC groups. An additional benefit was lower (p < 0.01) cholesterol content from 66.9 mg/100 mg (NC) to 62.8 mg/100 mg (FDBG5 or 10%) in thigh meat. Furthermore, the least cost feed/kg body gain was achieved in FDBG10% and DBG5%+Enz groups, with approx. 16% reduction compared to NC cost, leading to increasing the income gross margin by 47% and 40% in FDBG10% and DBG5%+Enz groups, respectively.

CONCLUSIONS

Substitution of corn-soybean based diet with 10% FDBG or 5% DBG+Enz resulted in better growth and higher economic efficiency of broilers chickens.

Risk factors for poor health and performance in European broiler production systems

BACKGROUND

Conventional broilers are currently one of the most efficient protein converters. Although decades of progress in genetic selection and feed formulation have lead to high standards of efficient broiler production, still a lot of variability is found between farms and between successive flocks. The aim of this study was to investigate risk- and/or protective factors for poor health and performance in conventional broiler-farms in Europe by developing eight multivariable linear mixed models. Three different models were used to investigate mortality (overall, first week, after first week), three models for performance variables (growth, feed conversion, European production index) and two models were related to slaughterhouse data (i.e. dead on arrival and condemnation rate).

RESULTS

Several factors related to management and housing were significantly associated with health and performance of broilers. The following factors were associated with increased mortality: floor quality, neonatal septicemia, ventilation type and other professional activities of the farmer. The factors associated with performance were chick sex, coccidiosis infections, necrotic enteritis, dysbacteriosis, light intensity adaptations, ventilation type, comparing daily flock results with previous flock results by farmer, daily check of feed and water system and type of feed. For dead on arrival three risk factors were identified i.e. daily growth, type of light adaptation and type of drinkers system. For condemnation rate seven risk factors were found, i.e. type of drinking system, daily growth, feed withdrawal time, type of ventilation, house size, septicemia after seven days and type of feed.

CONCLUSIONS

These results imply that a multifactorial approach is required with adaptations involving both improvements in management, housing, health programs and an increasing level of professionalism of the farmer in order to improve broiler performance and health.

Dietary inclusion of fibrous ingredients and bird type influence apparent ileal digestibility of nutrients and energy utilization

The interaction between inclusion of fibrous ingredients and bird type on the coefficient of apparent ileal digestibility (CAID) of nutrients and energy utilization was investigated in the current study. A 2 × 3 factorial arrangement of treatments was utilized with 2 fiber contents (10.3 and 19.3 g/kg neutral detergent fiber) and 3 bird types (broilers, pullets and layers). The low-fiber diet was based on corn and soybean meal, and the high-fiber diet was developed by the inclusion of palm kernel meal, canola meal, and oat hulls. Titanium dioxide was used as an inert marker to calculate the CAID. The digesta were collected from the terminal ileum following the feeding of experimental diets for 7 d. Significant interactions (P < 0.05) between dietary fiber content and bird type were observed for the CAID of DM, starch, fat, neutral detergent fiber and energy, and AMEn. In general, the CAID coefficients were higher in broilers, intermediate in pullets, and lowest in layers at both fiber contents. The CAID of nutrients in the 3 bird types was higher (P < 0.05) in the high-fiber diet than in the low-fiber diet, but the magnitude of responses differed. Layers showed markedly higher digestibility responses to increased dietary fiber content compared to broilers and pullets. There were interactions (P < 0.05 to 0.001) between the dietary fiber content and bird type for the CAID of nitrogen and all amino acids, except for Asp and Lys. The CAID of Asp and Lys was highest (P < 0.05) in broilers, intermediate in pullets, and lowest digestibility in layers. The CAID coefficients of nitrogen and amino acid increased with increased fiber content, with distinctly greater responses in layers compared to broilers and pullets. Overall, layers showed greater digestibility of nutrients in response to the increased fiber content, suggesting that layers require high-dietary fiber contents to efficiently utilize nutrients compared to broilers and pullets.

Parâmetros zootécnicos e desenvolvimento da moela de frangos de corte em dietas de sorgo grão e a inclusão de carotenoides

RESUMO Objetivou-se avaliar a substituição do milho pelo sorgo grão, moído ou inteiro, e a inclusão de carotenoides sintéticos em rações de frangos de corte, sobre parâmetros zootécnicos e desenvolvimento da moela. Utilizaram-se 960 frangos, machos e fêmeas, da linhagem Cobb 500, que foram submetidos a quatro dietas: à base de milho (M), à base de sorgo moído (SM) ou ainda acrescido de carotenoides sintéticos (SMC) e à base de sorgo inteiro (SI). Foram avaliados peso vivo, consumo de ração, conversão alimentar, rendimento de carcaça e cortes, peso de moela. A ração de SI proporcionou maior desenvolvimento de moela, embora, aos sete dias, não tenha havido diferenças no peso vivo e na conversão alimentar entre as dietas. SM e SMC proporcionaram maiores valores de peso vivo aos 28 dias do que SI. As conversões alimentares real e tradicional aos 40 dias foram semelhantes para as rações de sorgo, com um melhor rendimento de carcaça em SM e SMC. O sorgo moído pode substituir integralmente o milho nas rações para frangos de corte, sem comprometimento de desempenho e rendimento de carcaça, e, na forma grão inteiro, é zootecnicamente viável.

Impact of corn particle size on nutrient digestibility varies depending on bird type

The interaction between bird type (broilers and layers) and corn particle size (fine, medium, and coarse) on the coefficient of apparent ileal digestibility (CAID) of DM, nitrogen (N), starch, fat, gross energy (GE), calcium (Ca) and phosphorus (P), and AMEn was investigated in a 2 by 3 factorial study of 6 dietary treatments. Whole corn was ground in a hammer mill to pass through screen sizes of 2.0, 5.0, and 8.0 mm for fine, medium, and coarse grades, respectively. A corn-soybean meal diet, mixed using the same batch of ingredients, was fed to both bird types. Titanium dioxide was included in all diets for digestibility measurements. 35-day-old Ross 308 male broilers and 59-wk-old Hy-Line Brown layers were used in this study. For each bird type, 108 birds of uniform body weights were accommodated in 18 replicates (6 replicates per particle size and 6 birds per replicate). The treatment diets were offered ad libitum for 7 d prior to the collection of ileal digesta. A bird type by particle size interaction was observed (P < 0.001) for the CAID of DM, starch and GE. In broilers, CAID of DM, starch and GE was unaffected by particle size, whilst in layers, increasing the corn particle size to medium and coarse resulted in a greater (P < 0.05) CAID for DM, starch and GE compared to fine particles. The CAID of N and fat was greater (P < 0.05) in broilers than layers and the opposite was observed (P < 0.05) for Ca and P. Regardless of bird type, coarse and medium-ground corn resulted in a greater (P < 0.05) Ca digestibility compared to finely-ground corn. Overall, broilers had a greater digestibility of nutrients than layers, except for Ca and P. Feeding medium and coarse corn particles benefited the CAID of DM, starch and GE in layers, suggesting that digestive system in these birds is probably more sensitive to feed particle size than broilers.

Whole pearl millet feeding does not impair performance and nutrient digestibility in 28-day-old broiler chickens

The effects of varying inclusion levels of whole grain millet in millet-soya bean-based diets on growth performance, gizzard development, digesta characteristics and nutrient digestion in broiler chicken were investigated. Starter (0-14 days) and grower (15-28 days) broiler chicken diets containing pearl millet at 500 and 540 g/kg diet, respectively, were formulated. The diets comprised of 0%, 20%, 40%, 60%, 80% and 100% of millet incorporated as whole grain. One-day-old unsexed Arbor Acres Plus chicks (n = 540) were allotted to the experimental diets in a completely randomized design with the diets and water provided ad libitum for 28 days. Each treatment was replicated seven times, and each replicate had 12 chicks. Results showed that daily live weight gain and feed conversion ratio of chickens on the whole millet grain diets compared favourably with chicken on the control in both starter and grower phases, while feed intake reduced quadratically (p < .05) with increased whole grain millet levels in the starter phase. Morphological and structural characteristics of the gizzard and small intestine and intestinal digesta pH and viscosity were also unaffected (p > .05) by whole grain millet inclusion levels. However, the weight of intact millet grain in gizzard increased linearly (p < .001) with whole grain millet inclusion in the diets. Dietary whole grain millet inclusion also consistently lowered (p < .05) jejunal and ileal maltase and sucrase activities, but did not influence (p > .05) pancreatic amylase activity. Ileal crude protein and starch digestibility increased, while ileal energy digestibility decreased significantly (p < .05) with whole grain millet inclusion. Whole grain millet inclusion in broiler starter and grower diets up to 500-540 g/kg did not negatively impact on broiler chicken performance.

Growth performance, carcass composition, leg bones, and digestive system characteristics in Pekin duck broilers fed a diet diluted with whole wheat grain

A total of 270 Pekin ducks were reared for 49 d to determine the effect of feeding a diluted complete commercial wheat grain diet on live weight, feed intake and conversion, carcass, leg bone, and digestive system traits. Different feeding regimes had a significant effect on the body weight of the ducks aged 35 d and the feed conversion ratio in the period between days 22 and 35 of rearing. Dilution of a complete commercial diet with whole wheat grain had no significant influence on the final live weight (day 49), feed intake, and feed conversion ratio during the entire rearing period. Ducks fed a diet with whole wheat grain had a significantly higher dressing percentage after higher percentage of pectoral muscles, skin with subcutaneous fat, abdominal fat, as well as a significantly lower percentage of carcass remainders at the age of 49 d. Dilution of a complete commercial diet with whole wheat grain had no impact on the length of the respective intestinal sections nor on the weight and percentage share of gizzard, liver, heart, and spleen. However, it significantly lowered the fracture strength of the tibiotarsus, and decreased some dimensions of the femur and tibiotarsus.

Influence of the particle size and form of feed on growth performance, digestive tract traits and nutrient digestibility of white egg-laying pullets from 1 to 112 D of age

The influence of the grinding and physical form of diets on growth performance, gastrointestinal tract (GIT) development and nutrient digestibility was studied in layer pullets from hatch to 112 d of age. Diet formed a 2 × 2 factorial with 2 hammer mill screen sizes to grind cereals (4 and 8 mm) and 2 forms (mash and crumble). A total of 864 1-day-old layer chickens were randomly assigned to 1 of the 4 treatment groups with 8 replicates (27 birds per replicate). Cumulatively, pullets fed crumbles consumed less feed (P < 0.05) and had better feed conversion ratio (FCR; P < 0.01) than those fed mash. Coarse grinding cereals (CG) improved FCR (P < 0.05) without significant change in cumulative feed consumption compared to that of fine grinding (FG). With regard to body weight gain (BWG), pullets benefited from crumbles from 1 to 56 d of age (P < 0.01). There were interactions (P < 0.05) between screen size and feed form in relation to FCR (1 to 28 d) and overall BWG. At 112 d of age, the relative weight (RW, g/100 g body weight) of the crop, gizzard, pancreas, and liver of crumble-fed birds were lower (P < 0.05) than those for birds fed mash. Pullets fed coarsely ground feed had higher RW of the crop, proventriculus, gizzard, liver, and caecum compared to those fed finely ground feed. Compared to mash feeding, pullets fed crumbles increased (P < 0.05) total tract digestibility of ether extract and crude protein and the activities of pancreatic amylase and lipase. Digestibility of ether extract (P < 0.05) and pancreatic amylase activity (P < 0.01) were higher in birds fed a CG diet than in birds fed the FG regimen. Regarding the nutrition of egg-laying pullets, crumbles might be preferred to mash feed when the main objective is to improve FCR. Data also suggested that cereals used for pullet feed can be ground more coarsely than is in current practice.

Influence of feed particle size and feed form on productive performance, egg quality, gastrointestinal tract traits, digestive enzymes, intestinal morphology, and nutrient digestibility of laying hens reared in enriched cages

A total of 640 Lohmann LSL hens were randomly allotted to 4 dietary treatments arranged in 2 × 2 factorial with 2 feed particle sizes (fine and coarse) and 2 feed forms (mash and crumble). The 2 particle sizes were achieved by grinding whole corn and wheat in the hammer mill to pass through 4- and 8-mm sieves. The laying hen diet was isonutritive, and each diet was fed to 8 enriched cages of 20 hens from 21 to 52 wk of age. Screen size and feed form did not affect feed intake, egg production, egg weight, egg mass, and quality traits of the eggs, except for yolk color score, which decreased with crumbling of the feed. Feed conversion ratio was greater (P < 0.01) in hens fed the coarsely ground diet than in hens fed the finely ground diet. Crumbling the feed increased (P < 0.01) feed intake and feed conversion ratio compared to those after mashing. The relative weight of the liver and length of the small intestines were greater (P < 0.05) in hens fed crumble than in hens fed mash. Finely grinding cereals decreased (P < 0.01) the pancreas and gizzard weight compared to those after coarse grinding. The pH of digestive organs showed significant responses to feed form. Crumbling resulted in increased (P < 0.01) pancreatic activities of amylase, while lipase secretion was not affected by the manipulations in screen size and feed form. Ileal villus measurements (villus height, villus height/crypt depth ratio, villus surface area) were greater (P < 0.01) in hens fed crumble than in hens fed mash, whereas particle size had no effect. Total tract digestibility coefficients of crude ash and ether extracts were improved narrowing screen size from 8 to 4 mm. Data illustrated that grinding cereals to pass through a 4-mm screen could improve the efficiency of feed conversion. However, feeding crumbles provided no benefit to productive performance and egg quality, although the absorptive capacity of laying hens increased.

Influence of feeding whole maize, differing in endosperm hardness, on the performance, nutrient utilisation and digestive tract development of broiler starters

Use of whole wheat, along with compounded feeds, for poultry feeding is a common practice in many parts of the world. However, studies investigating the use of other grains are limited. In the present study, the influence of including whole maize, with differing hardness, in broiler diets on the performance, nutrient utilisation and digestive tract development was examined. The experimental design was a 3 × 2 factorial arrangement of treatments, evaluating maize hardness (hard, semi-hard or soft) with diets based on ground maize or 115 g/kg whole maize replacing ground maize. The three maize cultivars were ground in a hammer mill to pass through a 4 mm sieve and six diets were developed based on one of the three cultivars. Following mixing, all diets were cold pelleted through a 3 mm die. Each of the six diets was fed to six replicate cages (eight birds per cage) from day 1 to 21 post-hatch. Maize hardness and whole maize inclusion had no effect (P>0.05) on weight gain. Maize hardness influenced (P<0.05) feed intake and feed per gain, while these two parameters were unaffected (P>0.05) by the inclusion of whole maize. The apparent metabolisable energy (AME) was unaffected (P>0.05) by maize hardness and whole maize inclusion. Maize hardness increased the ileal digestibility of nitrogen (P<0.05) and starch (P=0.06). The relative weight of the gizzard was greater (P<0.05) in birds fed hard and semi-hard maize compared to soft maize, and was greater (P<0.05) when whole maize was included. These results indicated that 115 g/kg of ground maize can be replaced by whole maize in broiler starter diets with no adverse effects on growth performance and thus can reduce the cost of feed manufacture.

Feeding whole grain and phytase to meat chickens: recent Australian experience

Both whole-grain feeding and exogenous phytases have been widely accepted by the chicken-meat industry, so any interactions that arise from this combined supplementation are potentially important. Nevertheless, there is a paucity of research evaluating the effect of phytase under whole-grain feeding regimens. Whole-grain feeding increases relative gizzard weights and gizzard functionality. However, the gizzard is the primary site of phytate degradation by phytase, so this combined supplementation should enhance phytase efficacy. Moreover, there has been recent progress towards understanding the influence of whole-grain feeding and exogenous phytase on broiler performance, which is discussed. Further research is warranted to establish a whole-grain feeding regimen that generates robust gizzard responses so as to enhance feed efficiency, energy utilisation and phytase efficacy.

Whole sorghum inclusion and feed form on performance and nutrient digestibility of broiler chickens

A total of 432, one-day-old broiler chickens were randomly assigned as a 2 × 4 factorial design (pellet or mash and 0, 25, 50, and 75% whole sorghum levels) in a completely randomised experiment, having six replicates with nine birds per replicate. Body weight and feed intake were measured on a pen basis at 10, 25, and 35 days of age and feed conversion ratio calculated. Pelleting diets significantly improved (P<0.05) feed intake, body weight and carcass yield of broiler chickens at 10 and 24 days of age. Heavier relative gizzard weights with lower pH (P<0.05) were recorded for broiler chickens offered mash diets at 35 days old. Feed conversion ratio at 35 days of age increased (P<0.035, quadratic effect) with higher levels of whole sorghum and levelled off at 75% inclusion rates. Relative gizzard weight at 35 days was marginally increased (P<0.033, linear effect) in line with rising sorghum levels. Similarly, relative bursa and liver weights at 35 days increased (P<0.037, quadratic effect and P<0.033, linear effect, respectively) with sorghum inclusion. The results showed that pelleted diets gave superior performance compared to mash diets. Although higher levels of sorghum inclusion in mash diets enhanced gizzard development, performance parameters of birds at 35 days of age were poorer, with 125 g less body weight and an increase in FCR from 1.51 to 1.62 for the 0% and 75% sorghum levels respectively.

Free choice feeding of whole grains in meat-type pigeons: 1. effect on performance, carcass traits and organ development

The effects of 5 different feeding systems on the performance, carcass traits and organ development were studied in pigeon squabs. The 5 treatments were (1) whole grains of maize, pea and wheat plus concentrate feed; (2)whole grains of maize and wheat plus concentrate feed (CWC); (3) whole grains of maize and pea plus concentrate feed; (4)whole grain of maize plus concentrate feed (CC); and (5) compound feed (CF). Feed intake of parent pigeons increased significantly from 0 to 21 d and it was higher in the CF treatment. Body weight of squabs in the CWC treatment was the highest among the 5 treatments in 4 weeks. Body weight losses of parental pigeons during the rearing period were not significantly different among the 5 treatments. Protein intake in CC and CWC treatments was lower than that of the other three treatments. The CWC treatment had the highest daily weight gain and the lowest feed conversion ratio. Treatments were statistically similar in the relative weight of carcass, breast and thigh. CF had the lower relative weight of abdominal fat. Relative weight of gizzard in the CF treatment was significantly lower than that of CWC. It was concluded that the application of free choice feeding of whole grains of maize and wheat plus concentrate feed increased the body weight of 28-d-old pigeon squabs and decreased the feed conversion rate of parent pigeons. This feeding strategy could be commercially interesting in meat-type pigeon production.

Effect of Feed Form and Whole Grain Feeding on Gastrointestinal Weight and the Prevalence of Campylobacter jejuni in Broilers Orally Infected

Two independent trials were carried out to evaluate the effect of feed form, whole wheat (WW) and oat hulls (OH) addition on gastrointestinal (GIT) weight and Campylobacter jejuni colonization in orally infected birds. In Trial 1, there were six treatments factorially arranged with two feed forms (mash vs pellets), and three levels of WW from 1-21/22-42d: 0/0, 7.5/15%, 15/30%. Broilers were allocated in cages (3 birds/cage, 12 cages/treatment). In Trial 2, there were three treatments: a mash diet, a mash diet including WW (7.5% from 1-21 and 15% from 22-42d), and a third treatment including also 5%OH. Broilers were allocated in floor pens (1 pen with 30 birds/treatment). At 14d, all broilers in Trial 1 or 3 broilers/pen in Trial 2 were orally challenged with 1.5 x 105 cfu of C. jejuni ST-45 /. In Trial 1, birds fed pelleted diets consumed 13.5% more feed, gained 31% more weight, and presented 12.9% better feed conversion for the whole trial (P<0.05). Pelleting decreased the relative weight of GIT and gizzard and increased the relative weight of proventriculus (P<0.05). Mash diets decreased pH in the gizzard (P<0.05). Inclusion of WW decreased the relative weight of proventriculus, increased gizzard weight, and reduced pH in the gizzard (P<0.05). At 21d of age, mash tended to reduce C. jejuni compared to pellets (7.85 vs 8.27 log10cfu/g; P = 0.091) and WW inclusion at 7.5/15% reduced C. jejuni colonization when compared to lower and higher inclusion (P<0.05). In Trial 2, birds fed T3 (WW+OH) showed 1.38 log10cfu/g less than birds fed Control diet (P<0.05). In conclusion, despite of the clear morphological changes in the GIT derived of FF and WW inclusion, no clear reductions in C. jejuni populations in the ceca were observed. However, WW and OH inclusion to mash diets significantly reduced cecal C. jejuni colonization at 42 days.

Effects of a Whole-grain Paddy Rice Diet on the pH Distribution in the Gizzard and Retention Time of Digesta in the Crop of Broiler Chicks

We previously reported that a diet containing 65% paddy rice suppressed the colonization of Campylobacter jejuni in the cecum of broiler chicks, suggesting that this type of diet has positive effects on upper gastrointestinal tract function in broilers. To reveal the possible mechanisms involved in this antibacterial effect of the whole-grain paddy rice diet, we performed experiments comparing the digesta passage rate in the crop and gizzard, the development of gizzard, and the pH distribution in the gizzard between groups of chicks fed two different diets, such as ground corn and whole-grain paddy rice. During these experiments, we made the following observations: the chicks in the group fed the whole-grain paddy rice diet had more developed gizzards and significantly larger crop content than the chicks in the group fed the ground corn diet. The chicks fed the whole-grain paddy rice diet retained the digesta in the crop for much longer and had less variation in the pH values in the gizzard than those fed ground corn. On the basis of these observations, we concluded that the hardness of the rice hull in whole-grain paddy rice leads to a larger amount and longer retention of content in the crop, as well as the uniformity of the internal pH of the gizzard, by promoting gizzard activity. We speculate that the hardness of the rice hulls promoted the grinding activity of the gizzard, resulting in the long retention time of the digesta in the crop and uniformity of the internal pH of the gizzard, which may sterilize or suppress Campylobacter growth in the gastrointestinal tract of broiler chicks.

Early intestinal growth and development in poultry

While there are many accepted "facts" within the field of poultry science that are in truth still open for discussion, there is little debate with respect to the tremendous genetic progress that has been made with commercial broilers and turkeys (Havenstein et al., 2003, 2007). When one considers the changes in carcass development in poultry meat strains, these genetic "improvements" have not always been accompanied by correlated changes in other physiological systems and this can predispose some birds to developmental anomalies (i.e. ascites; Pavlidis et al., 2007; Wideman et al., 2013). Over the last decade, there has been increased interest in intestinal growth/health as poultry nutritionists have attempted to adopt new approaches to deal with the broader changes in the overall nutrition landscape. This landscape includes not only the aforementioned genetic changes but also a raft of governmental policies that have focused attention on the environment (phosphorus and nitrogen excretion), consumer pressure on the use of antibiotics, and renewable biofuels with its consequent effects on ingredient costs. Intestinal morphology has become a common research tool for assessing nutritional effects on the intestine but it is only one metric among many that can be used and histological results can often be interpreted in a variety of ways. This study will address the broader body of research on intestinal growth and development in commercial poultry and will attempt to integrate the topics of the intestinal: microbial interface and the role of the intestine as an immune tissue under the broad umbrella of intestinal physiology.