Influence of non starch polysaccharide-degrading enzymes on the meat yield and viscosity of jejunal digesta in broilers fed wheat/barley-based diet

This study was conducted to investigate the effect of four commercial multi-enzymes on the performance, meat yield, water intake, litter moisture and jejunal digesta viscosity of chicks fed wheat/barley based diet. A total of 195 1-d-old male broiler chicks (Ross 308) were allocated to 5 treatment groups, with 3 replicates per treatment group and 13 birds per replicate pen and all data were analyzed in a randomized complete block design. During the starter period, feed conversion ratio (FCR) was significantly (P < 0.05) decreased by only enzymes A, B and D. Moreover, FCR was significantly (P < 0.05) decreased by all enzymes in grower and entire periods. The relative weight of the breast as proportion of live weight was significantly (P < 0.05) decreased by only enzyme A. The relative weight of the abdominal fat as proportion of live weight was also significantly (P < 0.05) increased by enzyme D. Enzyme supplementation decreased viscosity of jejunal contents of chicks at day 28, but only enzymes A and D reduced significantly (P < 0.05) the viscosity of jejunum compared to control diet. In conclusion, there were similar improvements on FCR of birds fed diets with enzyme supplementation and choice preference of enzyme supplementation has to be base on its economic value

Effects of &#946-Mannanase on broiler performance, gut morphology and immune system

An experiment was designed to assess the effects of graded levels of β-mannanase on performance, gut morphology and some blood proteins and leucocytes of broilers provided with diets based on corn and soybean meal. Broiler chickens are divided four group and supplied diet which contains 0, 500, 700, or 900 g/ton β-mannanase. Each treatment contained 4 pen with 15 birds/pen. 900 g/ton β- mannanase supplementation significantly reduced feed intake but did not influenced body weight gain and feed conversion ratio in both finisher and total period. 900 g/ton β-mannanase supplementation increased (P < 0.01) villus height and crypt depth and decreased (P < 0.01) goblet cell number, epithelial thickness and ratio of crypt depth to villus height in different sections of small intestine, suggesting that β-mannanase improves gut morphology in broiler chickens. The addition of β- mannanase at 700 and 900 g/ton to the diets significantly (P < 0.05) reduced jejunal viscosity compared with the control group. β-mannanase did not influence the blood serum proteins (albumin, alpha 1-, alpha 2-, beta and gamma-globulins) eosinophils and monocytes, but the addition β-mannanase increased lymphocyte, and decreased heterophil and heterophil: lymphocyte (H:L) ratio (p < 0.05). Thus it improved chickens immune system.Key words: Broiler, leucocytes, viscosity, serum proteins

Effect of dietary dilution of energy and nutrients during different growing periods on compensatory growth of Ross broilers

A completely randomized design was conducted to evaluate the effect of dietary dilution of energy and nutrients during different growing periods on compensatory growth of Ross broilers. Four replicant pens were assigned per seven treatments. Chicks in each treatment received concentrated and diluted diets in different stages of growing periods (starter, grower and finisher). The diets were mainly based on maize and soybean meal and had constant ratio of metabolizable energy/nutrients. It was concluded that feed intake, feed conversion, production index, feed cost and metabolizable energy per weight gain of chicks receiving concentrated diets during all stages of growing periods were the same as the chicks receiving diluted diets during finisher period (P > 0.05). The amount of abdominal fat was significantly lower in chicks receiving diluted diets during finisher period (P &#8804 0.05). Mortality percentage in chicks receiving concentrated diets during all stages of growing periods was significantly more than other treatments (P &#8804 0.05). Based on the results of the experiment, diluted diets for finisher period of Ross broilers male chicks is suggested

Study of possible reduction or withdrawal of vitamin premix during finisher period in floor and battery cage broiler raising systems

The effect of dietary vitamin premix withdrawal or reduction between 29 and 35, 36 and 42, and 29 and 42 days of age on broiler chicken performance and immunocompetence was evaluated. The diets were formulated based on wheat and barley, and the experiment was conducted in floor pens (experiment 1) and battery cage (experiment 2) rearing systems in 7 treatments and 4 replicates for each treatment. The results of experiment 1 showed that vitamin premix reduction and withdrawal at 29 days of age did not impair performance during the final period of broiler chicken (29 to 42 days). The results of experiment 2 showed that there were no significant differences in performance with reduction or withdrawal of vitamin premix from diets in 29 to 35 days, but in 36 to 42 days of age, performance of birds fed with a diet that has no vitamin premix (T1) was significantly lower than other treatments (P < 0.05). The results of the two experiments demonstrated that immunocompetence response was not affected by treatments in the finisher period (P > 0.05). In conclusion, the results of this study indicated that in the battery cage system, it is possible to reduce dietary vitamin premix during finisher period, but withdrawal can negatively affect performance of broiler chickens, while in the floor system, it is possible to withdraw vitamin supplements in broilers’ finisher diets.Key words: Vitamin premix, reduction, broiler, wheat, immunocompetence

Impact of dietary glutamine on amino acid digestibility values and intestinal morphometric parameters in neonate chicks

Two experiments were conducted to investigate the effects of fortification of the pre-starter diet with glutamine in post-hatch broiler chicks. In the first experiment, male chicks were used to study the impact of glutamine supplementation at three levels (0%, 1% and 2%) on performance, apparent faecal digestibility (AFD) and ileal digestibility (AID) of amino acids (AAs), as well as intestinal morphometric parameters from 0 to 14 days old. The best performance was obtained at 1% supplementation. Average daily feed intake and feed conversion ratio (FCR) were affected by treatments. Supplementing diets with glutamine resulted in increase of digestibility values for arginine (Arg), lysine (Lys), isoleucine (Ile) and valine (Val). Glutamine-supplemented diets led to higher villus height (VH) and shallower crypt depth (CD) in the jejunum and ileum. A second experiment was performed to investigate whether the form of glutamine could affect performance and morphometric parameters in newly hatched chickens. A control diet was prepared, based on casein as the sole source of protein-bound AAs. Three diets based on synthetic AAs were used to obtain nutrient values of the control diet, which were supplemented with a synthetic form of glutamine, glutamic acid and a 50 : 50 ratio of glutamine : glutamic acid. Chickens fed the control diet presented higher average daily weight gain and better FCR. None of the AID coefficients of amino acids were influenced by the dietary treatments, except glutamic acid and aspartic acid, which were decreased in chicks fed synthetic AAs. In conclusion, 1% glutamine supplementation improved performance, morphometric parameters and AID and AFD values of cationic AAs. The form in which dietary glutamine was provided could affect performance.Keywords: Amino acid, broiler, digestibility, intestinal morpholog

Effects of feeding strategy, fiber source of the diet, and crude protein content on productive performance of broiler breeder hens

A 12-wk experiment was conducted to investigate the effect of feeding program, dietary fiber, and CP content of the diet on productive performance of Ross broiler breeder hens (41 wk of age). There were 12 treatments arranged factorially with 2 levels of CP (14.5 vs. 17.4%), 3 fiber sources (0 vs. 3% inulin vs. 3% cellulose), and 2 levels of feed intake (160 vs. 208 g/d) that corresponded to restricted (R) or ad libitum (AL) feeding systems. The experimental diets contained 2,800 kcal ME with either 0.65 (14.5% CP) or 0.78% Lys (17.4% CP)

Potential probiotic of Lactobacillus johnsonii LT171 for chicken nutrition

The objective of this research was to investigate the potential probiotic of Lactobacillus johnsonii LT171. It had aggregation (60 min) and antibacterial effects against Salmonella Enteritidis, Salmonella Typhimurium and Escherichia coli O78:K80. It showed amylase and protease activity and high clear zone in culture medium containing calcium phytate; cell surface hydrophobicity, 85.21 ± 7.27%; resistance to acidic condition (pH 3 for 90 min) and bile salts (in culture medium containing 0.075% ox gall). Also it had resistance to nalidixic acid and neomycine. This research showed appropriate probiotic properties of L. johnsonii LT171 for chicken nutrition. Hence this strain can complement the characteristics of other strains in multistrain probiotics because of its high clear zone in culture medium containing calcium phytate

Effect of wheat inclusion and xylanase supplementation of the diet on intestinal enzyme activity, nutrient retention and performance in laying hen from 25 to 47 wks of age

A trial was conducted to examine the effects of increasing levels of wheat in the diet and xylanase (ES) supplementation on nitrogen and ether extract retention, pH of the GIT, productive performance from 25 to 47 wks of age, and enzyme activity at the small intestine level. The basal diets (from 25 to 33 wks and from 33 to 47 wks) consisted of soybean meal and corn, and the wheat was introduced in the experimental diets at expenses of corn, primarily

Effects of glycine and glutamic acid supplementation to low protein diets on performance, thyroid function and fat deposition in chickens

Consumption of low crude protein (CP) diets causes elevation in fat accumulation in chickens, and this effect is independent of dietary essential amino acid levels. Thyroid hormones, because of their metabolic regulatory characteristics, might be an effective factor in lipogenesis. Therefore, a study was conducted to investigate the influence of low CP diets on hormonal function of the thyroid. Two hundred and sixteen male broiler chicks, 10 - 25 days of age, were fed experimental diets that contained 230, 210, 190 and 170 g CP/kg with adequate amounts of total and digestible essential amino acids at or above NRC (1994) recommendations. Two other diets were the same as the 190 and 170 g CP/kg diets but contained additional glycine and glutamic acid. Reduction in CP below 190 g/kg led to a decline in body weight and feed intake and an increase in fat deposition in body, as would be expected. Plasma T4 concentration decreased significantly in the birds on the 170 g CP/kg diet and supplementation of glycine and glutamic acid had no effect on hormonal levels of the thyroid despite the reduction in whole-body and abdominal cavity fat deposition. Plasma T3 concentration was not affected. Therefore, it is concluded that a reduction in circulatory levels of T4 that occurs in broiler chicks fed diets containing below 190 g CP/kg though with adequate essential amino acids, may be an effective method of increasing fat deposition. Keywords: Crude protein, nonessential amino acids, T3, T4, lipid depositio