The impact of cereal non-starch polysaccharides on intestinal development and function in broiler chickens

Increasing digesta viscosity altered nutrient transporter gene expression and decreased nutrient utilisation in Eimeria-challenged birds

1. Two experiments were conducted, the first was to investigate the effect of increasing digesta viscosity by dietary carboxymethyl cellulose (CMC) on the growth performance and intestinal morphology and characteristics of healthy birds. The second experiment evaluated the impact of increased digesta viscosity in birds during an Eimeria spp. challenge.2. In experiment 1, a corn-soybean meal-based basal diet was supplemented with 0, 10 or 20 g/kg CMC at the expense of cornstarch and offered to seven birds in each of eight replicate cages per diet from d 8 to 22 post hatching.3. Increasing digesta viscosity due to dietary CMC linearly reduced (p < 0.05) body weight (BW) gain and the apparent ileal digestibility of nutrients. The relative lengths of the duodenum, jejunum and ileum linearly increased (p < 0.01) with dietary CMC inclusion.4. In experiment 2, on d 14, 256 broiler chickens were randomly assigned to eight replicate cages in a 2 × 2 factorial arrangement of treatments with two CMC concentrations (0 or 10 g CMC/kg of diet), with or without an Eimeria challenge. On d 15, birds in the challenge groups were orally gavaged with a 1 ml solution containing 25,000, 25,000 or 125,000 oocysts of E. maxima, E. tenella and E. acervulina; or 1% PBS, respectively.5. Increasing digesta viscosity in Eimeria-challenged birds decreased the total tract digestibility of dry matter and gross energy (p < 0.05). The ileal gene expression of glucose transporters was upregulated (p < 0.05) in challenged birds that received the CMC-supplemented diet.6. In summary, increased digesta viscosity induced changes in the expression of nutrient transporter genes and decreased nutrient utilisation in Eimeria-challenged birds.

Effect of dietary supplementation with algae extracts on growth performance and caecal microbiota of broiler chickens

1. The objective of this study was to test the dose response of dietary supplementation with algae extracts rich in marine-sulphated polysaccharides (MSP1 and MSP2) on the growing performance, body composition at slaughter and caecal microbiota of broiler chickens.2. Male broiler Ross 308 chicks 1-d-old were distributed into eight groups, a control group (unsupplemented), four groups supplemented with increasing doses of algae extract MSP1 (40, 81, 121 and 162 g/ton feed) and three groups supplemented with increasing doses of algae extract MSP2 (40, 81 and 162 g/ton feed). Each group comprised six pens of 56 chickens.3. All chickens were reared under challenging conditions, i.e. high rearing density of 42 kg/m2, fed growing and finishing diets containing, palm oil, rye and high levels of wheat and subjected to short daily fasting periods. The growth performance was recorded during rearing. At 10, 22 and 31 d of age, 12 chickens per group were euthanised to collect the caecal contents and determine microbiota composition and short-chain fatty acid levels. At d 35, the quality of litter and the condition of feathers, footpads and tarsals were scored. At d 36, 7 chickens per pen were slaughtered under commercial conditions to determine carcass composition and breast meat quality (ultimate pH and colour).4. Algal extract MSP1 increased the weight of the caeca and butyrate concentration in the caeca at d 22 (p ≤ 0.05). It increased the ultimate pH of breast fillet measured after slaughter at d 36 (p ≤ 0.05). Moreover, the group receiving 162 g/t MSP1 had a more diverse microbiota at d22. However, algal extract MSP2 had negligible effect on the different measured parameters.

Effects of phytase supplementation on broilers fed with calcium and phosphorus-reduced diets, challenged with Eimeria maxima and Eimeria acervulina: influence on growth performance, body composition, bone health, and intestinal integrity

An experiment was conducted to evaluate the effects of phytase in calcium (Ca) and available phosphorous (avP)-reduced diet on growth performance, body composition, bone health, and intestinal integrity of broilers challenged with Eimeria maxima and Eimeria acervulina. A total of 672 14-day-old male broilers were allocated to a 2 × 4 factorial arrangement with 6 replicates per treatment and 14 birds per replicate. Two factors were Eimeria challenge and 4 dietary treatments: 1) a positive control (PC; 0.84% Ca and 0.42% avP); 2) a negative control (NC; 0.74% Ca and 0.27% avP); 3) NC + 500 FTU/Kg of phytase (NC + 500PHY); and 4) NC + 1,500 FTU/Kg of phytase (NC + 1500PHY). On d 14, birds in the Eimeria-challenged groups received a solution containing 15,000 sporulated oocysts of E. maxima and 75,000 sporulated oocysts of E. acervulina via oral gavage. At 5 d postinoculation (DPI), the challenged birds showed a higher (P < 0.01) FITC-d level than the unchallenged birds. While the permeability of the NC group did not differ from the PC group, the phytase supplementation groups (NC + 500PHY and NC + 1500PHY) showed lower (P < 0.05) serum FITC-d levels compared to the NC group. Interaction effects (P < 0.05) of Eimeria challenge and dietary treatments on feed intake (FI), mucin-2 (MUC2) gene expression, bone ash concentration, and mineral apposition rate (MAR) were observed. On 0 to 6 and 0 to 9 DPI, Eimeria challenge decreased (P < 0.01) body weight (BW), body weight gain (BWG), FI, bone mineral density (BMD), bone mineral content (BMC), bone area, fat free bone weight (FFBW), bone ash weight, bone ash percentage and bone ash concentration; and it showed a higher FCR (P < 0.01) compared to the unchallenged group. The reduction Ca and avP in the diet (NC) did not exert adverse effects on all parameters in birds, and supplementing phytase at levels of 500 or 1,500 FTU/Kg improved body composition, bone mineralization, and intestinal permeability, with the higher dose of 1,500 FTU/Kg showing more pronounced enhancements. There was an observed increase in FI (P < 0.01) when phytase was supplemented at 1,500 FTU/Kg during 0 to 6 DPI. In conclusion, results from the current study suggest that dietary nutrients, such as Ca and avP, can be moderately reduced with the supplementation of phytase, particularly in birds infected with Eimeria spp., which has the potential to save feed cost without compromising growth performance, bone health, and intestinal integrity of broilers.

Barley, an Undervalued Cereal for Poultry Diets: Limitations and Opportunities

Simple Summary

With the ever-increasing demand for poultry products, the continuous supply of conventional cereal grains such as maize has become a challenge. Barley has been recognised as a potential alternative feed ingredient that can replace common cereal grains in poultry diets. However, due to several limitations such as the presence of various anti-nutritive factors and the variability in nutrient composition and quality, the use of barley in poultry diets remains comparatively low. The previous findings on the optimum use of barley in poultry diets are also inconsistent primarily due to differences in research methodologies. The importance of using accurate nutrient profiles for specific barley cultivars to formulate barley-based diets is emphasised in this review. Moreover, the need to adapt feed processing conditions suitable to different barley cultivars to increase the inclusion of barley in poultry diets is highlighted in this review.

Abstract

The supply of conventional cereal grains, especially of maize, will be a significant constraint to the future growth of the poultry industry. Various alternative feed ingredients are being tested to replace maize in poultry diets. Barley (Hordeum vulgare L.) is one such feed ingredient, the use of which remains limited in poultry diets due to its low metabolisable energy, presence of anti-nutritive, soluble non-starch polysaccharides and consequent inter-cultivar variability. Differences in research methodologies used in published studies have also contributed to the inconsistent findings, preventing a good understanding of the nutritional value of barley for poultry. The importance of using accurate nutrient profiles, specifically metabolisable energy and digestible amino acids, for specific barley cultivars to formulate barley-based diets is emphasised. Nutritionists should also pay close attention to feed processing conditions tailored to the specific barley cultivars to increase the barley inclusion in poultry diets.

Dietary Soluble Non-Starch Polysaccharide Level Influences Performance, Nutrient Utilisation and Disappearance of Non-Starch Polysaccharides in Broiler Chickens

This study evaluated the effect of dietary soluble non-starch polysaccharides (sNSP) on performance and nutrient utilisation in broilers from d 0 to 35. Cobb 500 broilers (n = 480, 80 birds per treatment) were fed either wheat- or corn-soybean meal-based diets formulated to contain either a high, medium, or low sNSP content, in a 2 × 3 factorial arrangement, fed as Starter (d 0−14) and Grower (d 14−35). Birds fed the low sNSP level presented greater BWG at d 0−14 and lower feed intake at d 14−35 compared to birds fed the medium sNSP level (p < 0.005). At d 14, birds fed the high sNSP level presented greater ileal and total tract starch digestibility and total tract sNSP degradability and insoluble NSP degradability, compared to feeding the low sNSP level. At d 35, total tract DM and metabolisability of gross energy was greater in birds fed the medium sNSP level compared to those fed the high or low sNSP level (p < 0.005). Generally, bird performance and nutrient utilisation was greater in birds fed the corn-based diets compared to the wheat-based diets. These results illustrate that dietary sNSP level and composition influences bird performance and nutrient digestibility.

Antioxidant Status, Blood Constituents and Immune Response of Broiler Chickens Fed Two Types of Diets with or without Different Concentrations of Active Yeast

Simple Summary

Rations for broilers can be safely supplemented with probiotics such as active Saccharomyces cerevisiae (SC) yeast to stimulate oxidative reactions and immune response against stress and infectious agents. The current study suggested that SC yeast enhanced antioxidant capacity, growth rate, immune organ weights, immune response and the survival rate of broilers after Avian Influenza virus challenge at 38 days of age.

Abstract

Probiotics, such as active yeasts, are widely used to enhance poultry production and reduce feeding costs. This study aimed to investigate the antioxidant and immune responses of broilers to different concentrations of active Saccharomyces cerevisiae (SC) when supplemented to two types of diets. A total of 216 1-day-old Arbor Acres unsexed chicks were used in a factorial design, involving two feeds (regular- versus low-density diet) and three concentrations of SC (0%, 0.02% and 0.04%). The results revealed that the low-density diet reduced the body weight and production index of broilers. The addition of SC improved the production index more than the control diet. Total antioxidant capacity (TAC), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and eosinophils were significantly higher in response to the regular-density diet than the low-density diet; however, phagocytic activity (PA), lymphocyte and lysozyme activity (LYS) were lower. Saccharomyces cerevisiae reduced ALT, AST, malondialdehyde (MAD) and TAC more than the standard set, but improved packed cell volume (PCV), hemoglobin (Hgb), red blood cells (RBCs), lymphocytes, monocytes, heterophils, phagocytic index (PI) and the immune response to Newcastle disease virus (NDV) and avian influenza (AI). In conclusion, supplementation of a regular- or low-density diet with SC at a concentration of 0.02% or 0.04% improved the antioxidant parameters, immune status and production index of broilers against stress and infectious agents.

Effect of graded dietary inclusion levels of hybrid rye grain on productive performance, the cost-effectiveness of nutrition and egg quality in laying hens

The study was designed to investigate productivity parameters, egg quality and the cost effectiveness of feeding laying hens with diets where ground wheat was replaced with varying levels of whole hybrid rye grain cv. Brasetto. A total of 396 Hy-Line Brown hens at 34 weeks of age were allocated to three treatment groups with 66 replicates (cages) of two hens each, and were fed isocaloric and isonitrogenous pelleted diets for 12 weeks. The diet for control group hens (R0) did not contain rye grain. In diets for hens from groups R100 and R200, ground wheat grain was partially replaced with whole rye grain at 100 g/kg and 200 g/kg, respectively. Whole intact rye grains were included in the diets. The cost of diets containing 10% and 20% of whole rye grain was by approximately 1.0% and 1.9% lower, respectively, compared with the control diet that contained no rye grain. During the entire 12-week feeding period, dietary treatments had no effect on laying rate (95.64% to 97.07%), egg weight (62.51 g to 62.74 g) or egg mass output (5.04 kg to 5.12 kg per hen). The inclusion of whole rye grain in layer diets caused a linear increase in feed intake (P < 0.047) and tended to linearly increase the feed conversion ratio (FCR, P = 0.078). Both groups of hens fed diets containing whole rye grain were characterized by a linear decrease in the dry matter (DM) content of excreta (P = 0.001). Increased excreta moisture was accompanied by a tendency towards a higher incidence of dirty eggshells in R200 hens (P = 0.068). The inclusion of 100 g/kg of whole rye grain in layer diets decreased the cost of feed per kg of eggs by 1.9%. Dietary treatments had no significant effect on eggshell thickness (0.330 mm - 0.345 mm), albumen quality (Haugh units, 83.46 – 85.84) or yolk color (3.8 - 4.0). The results of this experiment indicate that pre-pellet inclusion of whole rye (at up to 200 g/kg) in diets with supplemental NSP-degrading enzymes and phytase can be an effective and economically viable alternative to ground wheat in pelleted layer diets.

Replacing Maize Grain with Ancient Wheat Lines By-Products in Organic Laying Hens’ Diet Affects Intestinal Morphology and Enzymatic Activity

The effects of replacement of maize grain with ancient wheat by-products on intestinal morphometry and enzymatic activity in laying hens was studied. Eighty hens were divided into two groups (40 each, 8 replicates, 5 hens/replicate) fed two isoproteic and isoenergetic diets. In the treated group, part of the maize was replaced by a mix of ancient grains (AGs) middling, in a 50:50 ratio of Triticum aestivum L. var. spelta (spelt) and Triticum durum dicoccum L. (emmer wheat). The AG diet affected the weight of all the large intestine tracts, decreasing the weight of caeca (p < 0.01) and increasing those of colon (p < 0.01), rectum and cloaca (p < 0.05). Villus height in the AG group was higher (p < 0.01) than the control for the duodenum and jejunum, while for the ileum, the control group showed the highest values (p < 0.01). The submucosa thickness was higher (p < 0.01) in the control group for the duodenum and ileum, while the jejunum for the AG group showed the highest (p < 0.05) submucosa thickness. The crypts depth was higher (p < 0.01) in the control group for the duodenum and ileum. Enzyme activity was enhanced by AGs (p < 0.01) in the duodenum. Regarding the jejunum, sucrase-isomaltase and alkaline phosphatase had higher activity (p < 0.05 and p < 0.01, respectively) in the AG group. In the ileum, sucrase-isomaltase showed higher activity (p < 0.01) in the control group, while alkaline phosphatase showed the highest values (p < 0.05) in the AG group. Overall, results suggested that the dietary inclusion of AGs exerted positive effects in hens, showing an improved intestinal function.

Effects of Garlic Powder and Satureja Khuzestanica Essential Oil on Male Ross 308 Chickens Performance, Blood Lipid Profile, Immune Responses, Intestinal Microflora, and Morphology

Background: Herbal antioxidants have beneficial effects on health and performance. Meanwhile, medicinal plants and their derivations are utilized as growth and immunity promoter. Objectives: This research aimed to evaluate the effects of garlic powder and Satureja Khuzestanica essential oil (SKEO) on broiler performance, blood lipid profile, immune responses, intestinal microflora, and morphology. Methods: In total, 400 male chickens were randomly divided into five groups. Treatments included garlic powder (2 and 4%) and SKEO (400 and 500 mg/kg). Those in the control group received no intervention. On the 35th day of the experiment, the immune system of subjects was investigated, and at the end of the study, performance and blood lipid profile were analyzed. Also, the jejunal and ileal contents were separated to investigate the intestinal morphology and microflora. Results: Administration of herbal extracts was associated with improved performance, such as feed intake, BWG, and FCR (P < 0.05). Treatments could diminish the serum concentrations of lipid profile, including cholesterol, triglycerides, and LDL (P < 0.05). Meanwhile, the number of harmful intestinal bacteria was reduced by garlic (4% of diet) and SKEO (500 mg/kg) treatments (P < 0.05). Also, morphological characteristics of the intestine were improved (P < 0.05). Herbal plant supplement remarkably increased the villus length, villus length to crypt depth, and villus area (P < 0.05), but did not affect the immune responses (P > 0.05). Conclusions: This study demonstrated that dietary inclusion of herbal extracts is potentially an effective strategy for improving health and performance in broiler chickens.

Effect of Different Levels of Multienzymes on Immune Response, Blood Hematology and Biochemistry, Antioxidants Status and Organs Histology of Broiler Chicks Fed Standard and Low-Density Diets

This study was executed to investigate the effect of supplementing three multienzyme levels (0, 0. 1, and 0.2%) with two types of diet [standard diet (SD) vs. low-density diet (LDD)] on immune response, blood hematology and biochemistry, antioxidant status, and organ histology of broilers during 1–38 days of age. A total of 216 unsexed 1-day-old Arbor Acres broiler chicks were randomly distributed, on a factorial design (2 × 3), to six treatments each with six replicates. There were six chicks per replicate. Results showed that LDD significantly decreased body weight gain (BWG) of broilers, but did not affect the European Production Efficiency Index (EPEI). Addition of multienzymes at both levels (0.1 and 0.2%) significantly increased BWG and improved EPEI, compared to the control diet. Alanine aminotransferase (ALT), aspirate aminotransferase (AST), malondialdehyde (MDA), lymphocyte, lymphocyte transformation test (LTT), and phagocyte activity (PA) were significantly higher for LDD than the SD, but eosinophil was lower. Supplementation of multienzymes significantly decreased ALT, AST, and MDA, compared to the control group, but increased packed cell volume (PCV), hemoglobin (Hgb), lymphocytes, and monocytes. Immune organs, such as spleen, thymus, and the bursa of Fabricius were significantly increased with multienzyme supplementation. It could be concluded that multienzyme supplementation at either 0.1 or 0.2% to SD or LDD improved EPEI and immune status of broiler chicks.

The effect of carbohydrases or prebiotic oligosaccharides on growth performance, nutrient utilisation and development of small intestine and immune organs in broilers fed nutrient-adequate diets based on either wheat or barley

BACKGROUND

Non-starch polysaccharides are large complex molecules and are found in cereal grains. This study was conducted to investigate the effect of carbohydrase enzymes or prebiotic oligosaccharides on growth performance, nutrient utilisation and weight of organs associated with the immune system in broilers fed wheat- or barley-based diets.

RESULTS

In wheat-based diets, feed intake was lower (P < 0.05) following xylo-oligosaccharide supplementation, whereas in barley-based diets feed intake was greater (P < 0.05) following β-glucanase supplementation. Gross energy digestibility was improved (P < 0.01) when either level of xylanase was added to wheat diets. Ileal digestible energy was greater (P < 0.01) in wheat diets including an additive compared with the control diet. In wheat diets, bursa weight was lower (P < 0.05) following xylo-oligosaccharide supplementation compared with the control treatment.

CONCLUSIONS

The current study showed that supplemented carbohydrases or prebiotic oligosaccharides could alter the development of immune organs or small intestine without any significant effect on growth performance in broilers receiving nutrient-adequate diets. © 2018 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The Efficiency of Xylanase in Broiler Chickens Fed with Increasing Dietary Levels of Rye

In this paper, we present a study on the evaluation of the effect of xylanase addition to a diet with an increasing content of modern hybrid rye (Brasetto variety) on the performance indices and viscosity of small intestine content in broiler chickens. A total of 560 1-day-old male Ross 308 chickens were randomly assigned to 1 of 10 treatments, each comprising 7 replicate cages, with 8 male birds per cage. A 5 × 2 factorial arrangement was employed, with five dietary levels of ground rye (0%, 5%, 10%, 15%, and 20%). All the diets were either unsupplemented or supplemented with xylanase (200 mg/kg of feed; with minimum xylanase activity 1000 FXU/g). In the starter rearing period (1⁻21 days of age), the inclusion of rye (without xylanase supplementation) to the diet, even at the lowest dietary level (5%), negatively affected body weight gain (p < 0.05); there was no effect on feed intake and feed conversion ratio. In older chickens (the grower-finisher rearing period; 22⁻42 days of age), none of the dietary levels of rye (5⁻20%) affected growth performance indices. Similarly, no significant effect of increasing dietary level of rye was found for the entire rearing period (1⁻42 days of age). Diet supplementation with xylanase improved body weight gain and feed conversion ratio in chickens from 1 to 21 days of age. No positive effect of enzyme was found in older birds. No significant effects of the experimental factors used were noticed on the results of slaughter analysis, i.e., the carcass yield, breast meat yield, abdominal fat, and relative weight of the liver and gizzard. A high dietary concentration of rye (20%) increased the viscosity of small intestine content (p < 0.05); however, diet supplementation with xylanase significantly alleviated this effect. The findings of this experiment indicated that modern hybrid rye grain may be used at a 20% dietary level in broiler diets during the second feeding phase, i.e., from 22 to 42 days of age, without any detrimental influence on growth performance indices, while enzyme (xylanase) positively affected body weight gain and feed conversion ratio in younger chicks (1⁻21 days of age).

Effect of Dietary Ginger (Zingiber officinale Roscoe) and Multi-Strain Probiotic on Growth and Carcass Traits, Blood Biochemistry, Immune Responses and Intestinal Microflora in Broiler Chickens

Simple Summary

In the last decade, there has been growing interest in the use of natural herbs and probiotics as alternatives to antibiotics in feeds to improve animal productivity and to maximize their potential output. Therefore, the objective of this study was to determine the effect of different levels of ginger powder and a commercial multi-strain probiotic in the diet on broiler performance, immune response, microbiota, haematology and carcass characteristics. Based on findings, dietary supplementation with both ginger or probiotics showed significant influence on birds’ immune response, probably because ginger had strong antioxidant activity and the probiotics stimulated the production of natural antibodies.

Abstract

A total of 225 day-old male broiler chicks (Ross-308) were randomly allocated to five treatment groups, with three replicates in a completely randomized design for 42 days. Birds were fed a basal-diet supplemented with: no additive (control-diet), multi-strain probiotic (Lactobacillus acidophilus, Lactobacillus casei, Enterococcus faecium and Bifidobacterium thermophilum), or 0.15, 0.20 and 0.25% ginger (Z. officinale) powder, respectively. The results show no significant differences among treatments for growth traits and carcass characteristics, whereas using probiotics and ginger at all levels resulted in a significant decrease of gizzard weight and abdominal fat compared to the control group. Dietary treatments did not affect blood biochemistry and antibody production against sheep red blood cells (SRBC), IgG and IgM; however, antibody titre was higher in birds fed 0.25% ginger than other diets after 7 days post injection. The Lactobacillus counts in ileal content of birds fed 0.20 and 0.25% ginger were higher compared to the other treatments. In conclusion, dietary supplementation with either ginger or probiotics showed a significant influence on birds’ immune response, probably because ginger had strong antioxidant activity and the probiotics stimulated the production of natural antibodies.

Xylanase supplementation improves the nutritive value of diets containing high levels of sorghum distillers' dried grains with solubles for broiler chickens

BACKGROUND

An experiment was conducted to investigate the effect of sorghum distillers' dried grains with solubles (sDDGS) and xylanase supplementation in broiler chicken diets. A total of 432 Cobb-500 day-old male broiler chicks were used in a 4 × 2 factorial design (0, 100, 200 or 300 g kg(-1) sDDGS with or without xylanase supplementation). Each treatment was replicated six times with nine birds per replicate in a 35 day study.

RESULTS

Feed intake was increased (P < 0.001) throughout the study with the inclusion of dietary sDDGS. Body weight gain (BWG) was unaffected except for the last 2 weeks of study, when birds that received 200 and 300 g kg(-1) sDDGS had higher (P < 0.001) BWG. Feed conversion ratio (FCR) increased (P < 0.05) as sDDGS in the diet rose to 100 g kg(-1) during the starter phase and the whole period of study. Over the starter period, xylanase supplementation improved (P < 0.05) FCR, particularly for the highest inclusion of sDDGS. Protein digestibility deteriorated (P < 0.001) as sDDGS in the diet rose to 300 g kg(-1) . Xylanase reduced (P < 0.001) the concentration of xylose in the ileum of birds. The activities of sucrase and maltase in the jejunal mucosa were reduced when birds were offered 200 and 300 g kg(-1) sDDGS. Incorporation of sDDGS increased (P < 0.01) the total short-chain fatty acid concentration in the caeca.

CONCLUSION

The results showed that diets containing large amounts of sDDGS will benefit from xylanase supplementation, particularly in terms of FCR.

Review: Prediction of variation in energetic value of wheat for poultry

Yegani, M. and Korver, D. R. 2012. Review: Prediction of variation in energetic value of wheat for poultry. Can. J. Anim. Sci. 92: 261–273. Variations in physical and chemical characteristics of wheat can significantly influence the energy availability of this feed ingredient for poultry. These variations can result in inefficiencies in the form of over- or under-formulation of the diets at commercial feed mills or on poultry farms. Therefore, having a clear understanding of the variations is of paramount importance in the formulation of poultry diets as they can have negative consequences for production performance of birds. There are a large number of factors that can contribute to variations in energy availability of wheat for poultry. This review is intended to briefly discuss these factors and also practical approaches that can be used to predict these variations. These approaches include measuring physico-chemical characteristics, in vivo digestibility trials, in vitro digestibility techniques, and near infrared reflectance spectroscopy (NIRS). There are limitations associated with physico-chemical and in vivo measurements. However, in vitro digestibility techniques are simple and fast and can provide data for database development and ongoing calibrations of NIRS systems. Near infrared reflectance spectroscopy has enormous potential to predict variations in wheat apparent metabolizable energy, leading to more accurate diet formulation.

Desempenho e rendimento de carcaça de frangos de corte alimentados com pectina na ração

Avaliou-se o efeito da ingestão contínua de pectina em 720 frangos de corte sobre o desempenho e rendimento de carcaça e o consumo de água. O delineamento foi inteiramente ao acaso, em esquema de parcela subdividida, com níveis de pectina 0, 1, 3 e 5%, e idade primeira, segunda, terceira, quarta, quinta e sexta semanas, com seis repetições por tratamento. A viabilidade criatória não foi influenciada pela pectina na ração. O peso vivo, o consumo de ração e o ganho de peso diminuíram, e a conversão alimentar aumentou com a ingestão de pectina aos 35 e 42 dias. Não houve efeito da pectina sobre o consumo de ração (CR) e o consumo de água (CAg) na terceira semana. Na sexta semana, o CAg e a relação CAg:CR aumentaram com a ingestão de pectina. Aos 35e 42 dias, todos os parâmetros avaliados para rendimento de carcaça e corte diminuíram com o aumento da ingestão da fibra, sendo que apenas o rendimento de coxa+sobrecoxa não sofreu influência aos 42 dias. Os dados mostram que a ingestão contínua de até 1% de pectina na ração mantém o desempenho máximo das aves e que o consumo acima desse nível prejudica os parâmetros zootécnicos e aumenta o consumo de água na fase de maior crescimento.

Effects of different levels of dried sweet potato (Ipomoea batatas) leaves inclusion in finisher ration on feed intake, growth, and carcass yield performance of Ross broiler chicks

The effect of supplementation with increasing levels of dried leaves of sweet potato (Ipomoea batatas) on feed intake, body weight gain, and carcass yield characteristics of finisher Ross broiler chicks was studied at Haramaya University, Ethiopia. Three hundred Ross broiler chicks aging 29 days and weighing 540 +/- 5.28 g (mean +/- SD) were randomly distributed to 15 pens, each with 20 chicks, representing five treatment rations each with three replications. Dietary treatments consisted of inclusions of dried leaves of sweet potato at levels of 0, 50, 100, 150, and 200 g/kg DM for treatments T1, T2, T3, T4, and T5, respectively. The experiment lasted for 28 days, during which, dry matter intake (DMI), body weight gain, and feed conversion efficiency; carcass yield characteristics; and weights and lengths of different parts of gastrointestinal tract were measured. Data were subjected to statistical analysis using SAS (1998). Inclusion of dried leaves of sweet potato at the level of 200 g/kg DM resulted in lower (P < 0.01) daily DMI as compared to chicks in control diet (T1). The daily body weight gain declined (P < 0.01) when the level of dried leaves of sweet potato in the diet was 150 and 200 g/kg DM. Inclusion of dried leaves of sweet potato up to 100 g/kg DM did not affect (P > 0.05) eviscerated carcass weight, and weights of drumstick with thigh and breast meat were not affected (P > 0.05) by inclusion of dried leaves of sweet potato up to 150 g/kg DM. The results of this study revealed that inclusion of dried leaves of sweet potato up to 100 g/kg DM in the finisher ration might be considered as the optimum level of supplementation when chickens are sold on live weight basis, but if birds are sold on eviscerated carcass weight basis, inclusion up to 150 g/kg DM might be economically feasible as it produced higher carcass yield components.

Factors affecting intestinal health in poultry

The gastrointestinal (GI) tract has the most extensive exposed surface in the body and is constantly exposed to a wide variety of potentially harmful substances. The GI tract acts as a selective barrier between the tissues of the bird and its luminal environment. This barrier is composed of physical, chemical, immunological, and microbiological components. A wide range of factors associated with diet and infectious disease agents can negatively affect the delicate balance among the components of the chicken gut and, as a result, affect health status and production performance of birds in commercial poultry operations. Phasing out of antibiotic growth promoters from poultry diets in Europe and recent moves toward reduction or removal of these compounds in other parts of the world including North America will likely change the microbial profile of the GI tract environment in commercial poultry. This paper reviews the GI tract from developmental, immunological, and microbial standpoints and then discusses factors that can affect health status of this system. Necrotic enteritis and coccidiosis and their interactions, and possible consequences of antibiotic growth promoter removal from poultry diets with respect to these diseases, are discussed in more detail.

Influence of a combination of formic and propionic acids added to wheat- and barley-based diets on the performance and gut histomorphology of broiler chickens

Day-old male chicks were used to test the effects of a combination of formic and propionic acids (CFP) added to wheat- and barley-based diets on the performance and gut histomorphology of broilers. The CFP, containing formic and propionic acids based on an inorganic phyllo-silicate carrier, was added to starter and grower broiler diets of standard (NRC, 1994) or lower nutrient density (LND) using different levels of wheat and barley. Body weight gain (BWG) and feed conversion ratio (FCR) of broiler chicks were significantly (P < 0.001) improved by CFP supplementation at 21 days of age regardless of nutrient density (ND). However, at 35 days of age CFP addition significantly (P < 0.001) increased BWG and FCR. Proventriculus weight was also significantly affected by the dietary treatments. Ileal viscosity was significantly (P < 0.05) affected by ND which was associated with wheat and barley contents, whereas feed viscosity was significantly (P < 0.05) affected by CFP supplementation. Villus height was significantly (P < 0.05) increased by the CFP supplementation. In the case of villus width, an interaction effect was observed: there was a significant (P < 0.05) decrease in the group fed the standard ND diet, but only a numerical decrease in the group fed the LND diet compared to control group. No significant effect of dietary treatment on the thickness of the lamina muscularis mucosae could be detected.

Response of naked neck (Nana) and normal (nana) broiler chickens to dietary energy levels in a subtropical climate

1. The comparative response of naked neck (Nana) broiler chickens and their normally feathered (nana) full sibs to varied dietary energy levels was assessed under natural ambient conditions in a subtropical climate in two separate trials, one in winter (19.0 to 26.0 degrees C) and the other in summer (28.1 to 37.4 degrees C). 2. The chickens were fed on diets with 10.9, 11.5 or 12.1 MJ ME/kg and with a constant protein content of 200 g/kg from 1 to 42 d of age. 3. Both genotypes showed similar body weight, food intake and food conversion efficiency at 42 d of age. Body weight and food conversion efficiency improved on the diet with the highest energy content. 4. Apparent retention (AR) of crude protein (CP) was higher in nana chickens than in their Nana sibs in the winter trial, while no differences were observed for AR of dry matter (DM), crude fibre (CF), ether extract (EE) or calcium. In the summer trial, no difference in nutrient retention was seen between the genotypes. Increasing dietary energy had a positive influence on AR of DM, CP and EE. 5. The relative weights of feathers and skin were lower in Nana chickens than in their normal counterparts. Ready-to-cook yields were greater at the high dietary energy content, while abdominal fat increased with increasing energy content. Nana chickens had more skin protein and less fat in breast muscle and skin than their normal sibs in the summer trial. 6. It was concluded that the Nana broiler chickens showed similar performance and did not differ in dietary energy requirements in comparison to their nana sibs under natural ambient conditions in a subtropical climate.

The dietary effect of different wheat cultivars for broiler chickens

1. An experiment was conducted to examine the variability in chemical composition of 16 wheat cultivars and to study how this variability affected the performance of broiler chickens given diets containing 650 or 815 g wheat/kg diet during the first 3 weeks of life. Intestinal viscosity, apparent fat digestibility and apparent metabolisable energy were determined with all diets. Intestinal pH and the relative weight of different parts of the intestine were measured in chickens fed on diets with the high wheat inclusion. 2. The 16 wheat cultivars varied in chemical composition, with protein content ranging from 112 to 127 g/kg dry matter, starch content from 658 to 722 g/kg dry matter and non-starch polysaccharides from 98 to 117 g/kg dry matter. The effect of the different wheat cultivars on the measured parameters was most pronounced in chickens fed on diets with 815 g wheat/kg diet (P<0.001). However, significant (P<0.001) differences between cultivars were still present at the lower wheat content. 3. Milling-quality wheats resulted in better performance (P<0.001) than feeding-quality wheats at the high inclusion, whereas such an effect could not be registered in diets at the lower wheat inclusion. These results indicate that some of the feeding wheats are comparable in quality to milling wheats when included at the concentrations which are more common in practical broiler diets. 4. Decreasing the wheat content in the diets resulted in significantly (P<0.001) better performance and considerably (P<0.001) lower intestinal viscosity (jejunum; 2.4 to 5.9 cps, ileum; 4.6 to 10.9 cps) than in chickens fed on diets with the higher wheat inclusion level (jejunum; 9.1 to 38.4 cps, ileum; 20.8 to 82.0 cps). 5. Diets with 815 g wheat/kg influenced pH in the caeca, but not in the ileum and gizzard. The relative weights of the gizzard and ileum differed significantly (P<0.05) between treatments, whereas those of duodenum, jejunum and caeca were not affected by dietary addition of the different wheat cultivars. 6. The present study demonstrated that the chemical composition and the nutritive value of Danish wheats for broilers vary markedly. The results indicated that the non-starch polysaccharide and especially the arabinoxylan content of wheat are important factors in the discussion of the result obtained. Poor correlations were seen between performance and AMEn and care should be taken when using AMEn values alone to predict the nutritive value of wheat and wheat-based diets.