Effect of Rolled or Extruded Flaxseeds in Finisher Diet on Pellet Quality, Performance, and n-3 Fatty Acids in Breast and Thigh Muscles of Broiler Chickens

An experiment was conducted to compare the effect of corn-soybean meal finisher (29-42d) diets containing flaxseeds (rolled or extruded) on pellet quality, performance, n-3 fatty acids (FA) and oxidative stability of meat in broiler chickens. Seven pelleted diets were provided in a 3×2 factorial arrangement with three flaxseed levels (5, 10, and 15%) and two processing methods (rolled or extruded) and a zero flaxseed diet (control). Birds fed diet containing 15% flaxseed had significantly lower weight gain and higher feed conversion ratio compared to those fed diets contained 0, 5 and/or 10% flaxseed. The type of flaxseed processing did not influence (P > 0.05) fatty acid profile and the MDA content in muscles. Chickens fed the control diet had relatively high levels of saturated and monounsaturated fatty acids and low levels of polyunsaturated fatty acids. Feeding diets contained flaxseed markedly reduced the levels of saturated fatty acids, monounsaturated fatty acids and increased polyunsaturated fatty acids, particularly the n-3 fatty acids in meat. It is concluded that the addition of 15% flaxseeds to finisher diet can increase n-3 fatty acids and lipid peroxidation in meat, while reducing growth performance of broiler chickens. However, feeding finisher diet containing 10% flaxseed compared to 5 or 15% flaxseed is of more practical to achieve an acceptable level of Omega-3 fatty acids in breast and thigh muscles without compromising the performance of broiler chickens

Genetic parameters for body weight, carcass chemical composition and yield in a broiler-layer cross developed for QTL mapping

The objective of this study was to estimate genetic and phenotypic correlations of body weight at 6 weeks of age (BW6), as well as final carcass yield, and moisture, protein, fat and ash contents, using data from 3,422 F2 chickens originated from reciprocal cross between a broiler and a layer line. Variance components were estimated by the REML method, using animal models for evaluating random additive genetic and fixed contemporary group (sex, hatch and genetic group) effects. The heritability estimates (h2) for BW6, carcass yield and percentage of carcass moisture were 0.31 ± 0.07, 0.20 ± 0.05 and 0.33 ± 0.07, respectively. The h2 for the percentages of protein, fat and ash on a dry matter basis were 0.48 ± 0.09, 0.55 ± 0.10 and 0.36 ± 0.08, respectively. BW6 had a positive genetic correlation with fat percentage in the carcass, but a negative one with protein and ash contents. Carcass yield, thus, appears to have only low genetic association with carcass composition traits. The genetic correlations observed between traits, measured on a dry matter basis, indicated that selection for carcass protein content may favor higher ash content and a lower percentage of carcass fat

Genetic improvement for production and health in broilers

The objective of present thesis was to optimize the genetic improvement of production and health traits in broilers. The genetic correlations among abdominal, subcutaneous, and intramuscular fat showed that there is a high genetic correlation between abdominal and subcutaneous fat (0.54), whereas the genetic correlation between abdominal and intramuscular fat is almost zero (0.02). Therefore selection for reduced abdominal fat does not change the intramuscular fat content and consequently meat quality. The genetic correlations were estimated on broilers of different ages (48, 63, and 70 d). The results indicated that increase in growth at 48 d was accompanied by increase in valuable parts (breast meat and back half); at 70 d it was accompanied by an increase in abdominal fat percentage. In addition, the genetic correlation of BW at 48 d between individual cage and group housing demonstrated a genotype by environment interaction for performance of birds in different housing systems. The present research showed that including indirect carcass measurements in the broiler breeding schemes resulted in improved genetic gain for breast meat percentage and reduced rate of inbreeding, which is desirable for long-term selection. The improved genetic gain resulted from increased accuracy of selection due to the own performance of selection candidates for carcass traits. The reliability of the indirect measurements influences the usefulness of these methods. The correlation between BW and ascites related traits in the cold conditions were estimated using mixture model analysis. The results indicated that the overall correlations between BW and ascites traits are dependent on the relative frequency of ascitic and non-ascitic birds in the population. Finally, estimated genetic parameters for production and health traits were used in a simulation to illustrate the consequences of including health related traits together with production traits in a sustainable breeding program. The results showed that a reduction of 6% of response in production traits was sufficient to offset the negative response in health traits

Genetic Properties of Some Economic Traits in Isfahan Native Fowl Using Bayesian and REML Methods

The objective of the present study was to estimate heritability values for some performance and egg quality traits of native fowl in Isfahan breeding center using REML and Bayesian approaches. The records were about 51521 and 975 for performance and egg quality traits, respectively. At the first step, variance components were estimated for body weight at hatch (BW0), body weight at 8 weeks of age (BW8), weight at sexual maturity (WSM), egg yolk weight (YW), egg Haugh unit and eggshell thickness, via REML approach using ASREML software. At the second step, the same traits were analyzed via Bayesian approach using Gibbs3f90 software. In both approaches six different animal models were applied and the best model was determined using likelihood ratio test (LRT) and deviance information criterion (DIC) for REML and Bayesian approaches, respectively. Heritability estimates for BW0, WSM and ST were the same in both approaches. For BW0, LRT and DIC indexes confirmed that the model consisting maternal genetic, permanent environmental and direct genetic effects was significantly better than other models. For WSM, a model consisting of maternal permanent environmental effect in addition to direct genetic effect was the best. For shell thickness, the basic model consisting direct genetic effect was the best. The results for BW8, YW and Haugh unit, were different between the two approaches. The reason behind this tiny differences was that the convergence could not be achieved for some models in REML approach and thus for these traits the Bayesian approach estimated the variance components more accurately. The results indicated that ignoring maternal effects, overestimates the direct genetic variance and heritability for most of the traits. Also, the Bayesian-based software could take more variance components into account

Effect of Different Levels of Mushroom Waste (Agaricus bisporus) with or without Probiotic on Growth Performance, Carcass Characteristics, and Breast Meat Quality in Broiler Chickens

The aim of this study was to investigate the effect of mushroom waste and probiotic levels on growth performance, carcass characteristics, and meat quality in broiler chickens. A 2 × 3 factorial arrangement with two levels of probiotic supplementation (0 and recommended rate) and three levels of mushroom waste inclusion (0%, 3%, and 6%) was used in a completely randomized design using male broiler chickens (Ross 308 strain). Different levels of mushroom waste and probiotic had no significant effect on body weight gain and feed conversion ratio in broiler chickens. Neither different levels of mushroom waste nor probiotic independently had any significant effect on carcass characteristics. However, the use of mushroom waste and probiotics significantly reduced the malondialdehyde content in chicken breast meat 30 days after storage (P). Breast meat pH value was significantly reduced by supplementation with probiotic 1 and 30 days after storage (P). In conclusion, under the conditions of this experiment, inclusion of mushroom waste, particularly at 6% level, numerically improved growth performance and was effective in preventing meat oxidation

The Performance and Incidence of Ascites in Broiler Chickens in Response to Feed Restriction and Meal Feeding Programs

An experiment was conducted to evaluate the effect of feed restriction (FR) and meal feeding (MF) on performance, carcass characteristics and related parameters to ascites in Ross 308 male broiler chickens. Five dietary treatments were 1) the control (ad libo. feeding), 2 )feed restriction from 7 to 14 days (FR14), 3) feed restriction from 7 to 21 days (FR21), 4) meal feeding from 7 to 14 days (MF14) and 5) meal feeding from 7 to 21days (MF21). All birds were fed adlibitum for the first week post hatch and after 21 days of age. Four replicate of 12 birds were allocated to each treatment. The results indicated FR and MF21 groups had significantly (

Effects of Nutrient Density and exogenous enzymesin Starter Diet on Performance, Intestinal Microflora, Gut Morphology and Immune Response of Broiler Chickens

ABSTRACT A total of 810 one-day-old, straight-run broilers were used to evaluate the effects of dietary nutrient density and feed additives included in the starter diet on their performance, intestinal microbiota, gut morphology, and immune response. A 3×3 factorial arrangement with three nutrient densities (100, 103.75 and 107.5%, as recommended) and three feed additives (no additives, 0.5 g/kg diet Maxi-Gen, and Maxi-Gen + Superzyme + Bio-Phytase at the rate of 0.5, 0.25 and 0.1 g/kg diet, respectively), fed from 1 to 10 d of age. Similar commercial corn-soy grower and finisher diets fed to all birds from 10-24 and 24-42 d of age, respectively. There was higher (p<0.05) body weight gain and lower (p<0.05) feed conversion ratio in chicks fed starter diet with 107.5% nutrient density and Maxi-Gen with or without exogenous enzymes compared with those fed control diet at 10 and 42 d of age. Lactobacilli and Bifidobacteria counts in the cecal content were increased linearly as dietary nutrient density increased in 10-d-old birds (p<0.05). Higher duodenal and jejunal villus height and villus height to crypt depth ratio (p<0.05) were measured in the birds fed the starter diets with 103.75% and 107.5% nutrient density at 5 and 10 d of age. Total anti-SRBC and IgM titers were significantly higher in the broilers fed the 107.5% nutrient density diet containing feed additives at 35 day of age. It is concluded that higher nutrient density and the inclusion of feed additives in the starter diet may improve the growth performance, gut morphology, and immune response of broiler chickens

Estimation of Genetic Parameters for Fat Deposition and Carcass Traits in Broilers

Abdominal and subcutaneous fat are regarded as the main sources of waste in the slaughterhouse. Fat stored intramuscularly is regarded a favorite trait related to meat quality. The objective of current study was to estimate genetic parameters for fat deposition in the 3 different parts of body and their relationships with other carcass traits. Traits were recorded for 1,752 females and 1,526 males from a meat-type chicken line. Heritability estimates for abdominal fat percentage, skin percentage as a measure of subcutaneous fat, and intramuscular fat percentage were 0.71, 0.24, and 0.08, respectively. Heritabilities of the other carcass traits were moderate to high (0.28 to 0.73). There was a high genetic correlation between abdominal fat weight and skin weight (0.54), whereas the genetic correlation between abdominal fat weight and intramuscular fat percentage was almost zero (0.02). The BW at 7 wk showed a positive genetic correlation with fat production traits, which were high for intramuscular fat percentage (0.87) and moderate for skin percentage (0.17) and abdominal fat percentage (0.13). Therefore carcass traits could be improved by selection for increased breast muscle and reduced abdominal fat without decreased intramuscular fa

Effect of Chicory Plant (Cichorium intybus L.) Extract on Performance and Blood Parameters in Broilers Exposed to Heat Stress with Emphasis on Antibacterial Properties

The antimicrobial effectiveness of different extracts of Chicory (Cichorium intybus L.) plant including methanolic, ethylic acetate, chloroformic, and aqueous extracts was evaluated by Disk Diffusion method. The ethylic acetate extract showed higher antibacterial activity against E. coli compared with others. Then, effects of different levels of ethylic acetate extract on growth performance and blood parameters of broilers subjected to high ambient temperature was investigated. The treatments were; a control diet, 3 levels of the Chicory ethylic acetate extract (150, 250, and 350 mg/kg feed) and one level of probiotic with 4 replicates of 20 broiler chicks in each. The temperature was increased to 35°C with 50% relative humidity for 5 h daily, starting from 11 d until 42 d of the experimental period. Results indicated that inclusion Chicory extract at 350 mg/kg and probiotic increased body weight gain and improved feed conversion ratio during 11-24 d and 0-42 d (P < 0.05). There were no significant differences in feed intake of broilers treated with Chicory extract and probiotic compared with control. The serum concentrations of triglyceride and very low-density lipoprotein significantly decreased in birds received Chicory extract at the levels of 250 and 350 mg/kg feed compared with the other treatments (P < 0.05).  No significant difference was observed between treated groups and control for serum high-density lipoprotein and low-density lipoprotein concentrations. It seems that dietary supplementation of Chicory ethylic acetate extract at levels higher than 250 mg/kg feed has growth promoting effect which can result in improving growth performance and decreasing blood lipids of broilers exposed to heat stress condition