Performance, carcass yield, and qualitative characteristics of breast and leg muscles of broilers fed diets supplemented with vitamin E at different ages

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of energy level in finisher diets and slaughter age of on the performance and carcass yield in broiler chickens

Male broilers were used to evaluate the effects of different energy levels in finisher diets and age of slaughter on performance, production pattern and carcass yield. Experimental design was a 2x3 factorial arrangement: energy level (ME) in the finisher diet (3,200 and 3,600 kcal ME/kg) and age of slaughter (42, 49 and 56 days), resulting in six treatments with four replicates. The finisher diet was fed only in the last week of the growing period. Characteristics evaluated were feed consumption (FC), body weight gain (WG), feed conversion (FC), energy intake (EI), caloric conversion (CC), efficiency production index, production pattern, and carcass yield. The results showed better WG and CC for broilers fed 3,200 kcal ME/kg finisher diet. Broilers slaughtered at 42 and 49 days of age had better performance and higher annual production than broilers slaughtered at 56 days of age. Carcass yield was influenced by slaughter age and better breast yield was seen at 49 and 56 days than at 42 days of age. It was concluded that 3,200 kcal ME/kg induced the best overall performance. Poultry houses were efficiently used when broilers were slaughtered at 42 days of age. Meat:bone ratio was improved for broilers slaughtered at 49 and 56 days of age.

Effect of nucleotides on broiler performance and carcass yield

This study aimed at evaluating the effect of nucleotides on the performance and carcass yield of broilers fed diets with no antibiotic growth promoters (AGP), anticoccidials, or animal feedstuffs. In the trial, 600 Ross 308 male broilers were distributed in a completely randomized experimental design into six treatments with four replicates of 25 birds each. Treatments consisted of a control diet (CD), CD + AGP, CD + 0.04%, CD + 0.05%, CD + 0.06%, and CD + 0.07% nucleotides. The experimental diets did not contain anticoccidials, and birds were vaccinated against coccidiosis at three days of age. No significant differences were detected among broilers submitted to the different treatments in none of the studied parameters. Under the conditions of this experiment, diets supplemented with nucleotides did not influence broiler performance or carcass yield at 42 days of age, and were not different from the feeds not containing any additive or with AGP.

Performance, carcass yield, and meat quality of free-range broilers fed wet grain corn silage

This study aimed at evaluating the effect of total replacement of dry corn by wet grain corn silage (WGCS) in the feed of label broilers older than 28 days of age on performance, mortality, carcass, parts, breast meat and thighs meat yields, and meat quality. A mixed-sex flock of 448 ISA S 757-N (naked-neck ISA JA Label) day-old chicks was randomly distributed in to randomized block experimental design with four treatments (T1 - with no WGCS; T2 - WGCS between 28 and 83 days; T3 - WGCS between 42 and 83 days; and T4 - WGCS between 63 and 83 days) and four replicates of 28 birds each. Birds were raised under the same management and feeding conditions until 28 days of age, when they started to have free access to paddock with pasture (at least 3m²/bird) and to be fed the experimental diets. Feed and water were offered ad libitum throughout the rearing period, which was divided in three stages: starter (1 to 28 days), grower (29 to 63 days), and finisher (64 to 83 days) according to the feeding schedule. During the short periods of WGCS use (group T2 during grower stage and T4 during the finisher stage), performance and mortality results were similar as to those of the control group (T1). At the end of the experiment, it was observed that the extended use of WGCS (T2 and T3) determined a negative effect on feed conversion ratio. However, the best results of breast meat yield were observed with birds fed WGCS since 28 days (T2). It was concluded that WGCS can replace dry corn grain for short periods during the grower and finisher stages with no impairment of meat quality and yield in slow growth broilers.

Ostrich (Struthio camellus) carcass yield and meat quality parameters

This article aimed at compiling recent studies on the main factors that influence ostrich meat quality and carcass yield. Few articles investigated the effect of subspecies, which generally are not even mentioned. There are important dietary effects, particularly those caused by dietary protein to energy ratio. Rigor mortis follow-up studies showed that there are no losses in meat quality when carcasses are hot-deboned. Age at slaughter influences some meat quality traits, such as tenderness and lipid content. Few effects of gender have been observed, and at the same age at slaughter, both male and female present the same meat quality traits.

Effect of dietary betaine supplementation on the performance, carcass yield, and intestinal morphometrics of broilers submitted to heat stress

The objective of this study was to evaluate the effect of betaine in methionine- and choline-reduced diets fed to broilers submitted to heat stress. In total, 1,408 male broilers were randomly distributed into eight treatments, according to 2 × 4 (environment x diet) factorial arrangement, with eight replicates of 2 birds each. Birds were reared environmental chambers under controlled temperature (25-26 °C) or cyclic heat-stressing temperature (25-31 °C). The following diets were tested: positive control (PC), formulated to meet broiler nutritional requirements; negative control (NC), with reduced DL-methionine and choline chloride levels; and with two supplementation levels of natural betaine to the negative control diet (NC+NB1 and NC+NB2). Live performance, carcass traits, and intestinal morphometrics were evaluated when broilers were 45 days of age. The results showed that all evaluated parameters were influenced by the interaction between environment and diet, except for breast meat drip loss. The breakdown of the interactions showed that birds fed the PC diet and reared in the controlled environment had greater breast drip loss than those submitted to the cyclic heat-stress environment. Birds submitted to cyclic heat stress and fed the PC diet presented the lowest feed intake. Feed conversion ratio was influenced only by diet. The FCR of broilers fed the NC+NB2 diet was intermediate relative to those fed the PC and NC diets. The addition of betaine in the diet, with 11.18% digestible methionine and 24.73% total choline reductions, did not affect broiler live performance, carcass yield, or intestinal morphometrics.

Effect of protein, carbohydrate, lipid, and selenium levels on the performance, carcass yield, and blood changes in broilers

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of phytase supplementation on performance, bone densitometry and carcass yield in broilers chicks

An experiment was conducted to evaluate the performance, bone densitometry and carcass yield of broilers chicks, using different levels of phytase enzyme. Nine hundred and sixty male one-day-old broiler chicks were used. The birds were distributed in a completely randomized experimental design, involving five treatments and six replications of 32 chicks each. The treatments consisted of a control diet for each phase, and four other diets were formulated adding growing levels of the phytase enzyme (250, 500, 750 and 1,000 FTU of phytase kg-1 feed). When adding the phytase enzyme, the nutritional matrix was valued to guarantee the same nutritional levels as the control diet. In general, the addition of phytase enzyme determined a linear decrease on the performance of the birds. However, the performance obtained with the level of 250 FTU phytase kg-1 feed were no different from the control treatment. The best bone density results were observed in the control treatment with no phytase, and the highest leg and thigh yield were obtained at the level of 514 FTU phytase kg-1.

Evaluation of a commercially available organic acid product on body weight loss, carcass yield, and meat quality during preslaughter feed withdrawal in broiler chickens: A poultry welfare and economic perspective

The effect of a commercial organic acid (OA) product on BW loss (BWL) during feed withdrawal and transportation, carcass yield, and meat quality was evaluated in broiler chickens. Two experiments were conducted in Brazil. Commercial houses were paired as control groups receiving regular water and treated groups receiving OA in the water. Treated birds had a reduction in BWL of 37 g in experiment 1 and 32.2 g in experiment 2. In experiment 2, no differences were observed in carcass yield between groups. Estimation of the cost benefit suggested a 1: 16 ratio by using the OA. In experiment 3, conducted in Mexico, significant differences on water consumption, BWL, and meat quality characteristics were observed in chickens that were treated with the OA (P < 0.05). These data suggest this OA product may improve animal welfare and economic concerns in the poultry industry by reducing BWL and improving meat quality attributes.

Beef and hog carcass yield /

"February 1974"

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

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estimates of genetic trend for carcass traits in a commercial broiler line

Data from the slaughter of 24,001 chickens that were part of a selection program for the production of commercial broilers were used to estimate genetic trend for absolute carcass (CW), breast meat (BRW), and leg (LW) weights, and relative carcass (CY), breast meat (BRY), and leg (LY) weights. The components of (co) variance and breeding values of individuals were obtained by the restricted maximum likelihood method applied to animal models. The relationship matrix was composed of 132,442 birds. The models included as random effects, maternal additive genetic and permanent environmental for CW, BRW, LW, CY, and BRY, and only maternal permanent environmental for LY, besides the direct additive genetic and residual effects, and as fixed effects, hatch week, parents' mating group and sex. The estimates of genetic trend were obtained by average regression of breeding value on generation, and the average genetic trend was estimated by regression coefficients. The genetic trends for CW (+ 6.0336 g/generation), BRW (+ 3.6723 g/generation), LW (+ 1.5846 g/generation), CY (+ 0.1195%/generation), and BRY (+ 0.1388%/generation) were positive, and they were in accordance with the objectives of the selection program for these traits. The genetic trend for LY(-0.0019%/generation) was negative, possibly due to the strong emphasis on selection for BRY and the negative correlations between these two traits.

Comparison of different models to estimate genetic parameters for carcass traits in a commercial broiler line

The effect of genetic and non-genetic factors for carcass, breast meat and leg weights, and yields of a commercial broiler line were investigated using the restricted maximum likelihood method, considering four different animal models, including or excluding maternal genetic effect with covariance between direct and maternal genetic effects, and maternal permanent environmental effect. The likelihood ratio test was used to determine the most adequate model for each trait. For carcass, breast, and leg weight, and for carcass and breast yield, maternal genetic and permanent environmental effects as well as the covariance between direct and maternal genetic effects were significant. The estimates of direct and maternal heritability were 0.17 and 0.04 for carcass weight, 0.26 and 0.06 for breast weight, 0.22 and 0.02 for leg weight, 0.32 and 0.02 for carcass yield, and 0.52 and 0.04 for breast yield, respectively. For leg yield, maternal permanent environmental effect was important, in addition to direct genetic effects. For that trait, direct heritability and maternal permanent environmental variance as a proportion of the phenotypic variance were 0.43 and 0.02, respectively. The results indicate that ignoring maternal effects in the models, even though they were of small magnitude (0.02 to 0.06), tended to overestimate direct genetic variance and heritability for all traits.