Carcass and meat quality traits of rabbits under heat stress

Rabbits are very sensitive to heat stress because they have difficulty eliminating excess body heat. The objective of the current study was to evaluate the effects of heat stress on slaughter weight, dressing percentage and carcass and meat quality traits of rabbits from two genetic groups. Ninety-six weaned rabbits were used: half were from the Botucatu genetic group and half were crossbreds between New Zealand White sires and Botucatu does. They were assigned to a completely randomized design in a 2 × 3 factorial arrangement (two genetic groups and three ambient temperatures: 18°C, 25°C and 30°C) and kept under controlled conditions in three environmental chambers from 5 to 10 weeks of age. Slaughter took place at 10 weeks, on 2 consecutive days. Meat quality measurements were made in the longissimus muscle. Actual average ambient temperature and relative humidity in the three chambers were 18.4°C and 63.9%, 24.4°C and 80.2% and 29.6°C and 75.9%, respectively. Purebred rabbits were heavier at slaughter and had heavier commercial and reference carcasses than crossbreds at 30°C; however, no differences between genetic groups for these traits were found at lower temperatures. No genetic group × ambient temperature interaction was detected for any other carcass or meat quality traits. The percentages of distal parts of legs, skin and carcass forepart were higher in crossbred rabbits, indicating a lower degree of maturity at slaughter in this group. The percentage of thoracic viscera was higher in the purebreds. Lightness of the longissimus muscle was higher in the purebreds, whereas redness was higher in the crossbreds. Slaughter, commercial and reference carcass weights and the percentages of thoracic viscera, liver and kidneys were negatively related with ambient temperature. Commercial and reference carcass yields, and the percentage of distal parts of legs, on the other hand, had a positive linear relationship with ambient temperature. Meat redness and yellowness diminished as ambient temperature increased, whereas cooking loss was linearly elevated with ambient temperature. Meat color traits revealed paler meat in the purebreds, but no differences in instrumental texture properties and water-holding capacity between genetic groups. Purebred rabbits were less susceptible to heat stress than the crossbreds. Heat stress resulted in lower slaughter and carcass weights and proportional reductions of organ weights, which contributed to a higher carcass yield. Moreover, it exerted a small, but negative, effect on meat quality traits. © 2012 The Animal Consortium.

Protective effect of mannan oligosaccharides against early colonization by Salmonella Enteritidis in chicks is improved by higher dietary threonine levels

Aims: To evaluate mannan oligosaccharide (MOS) and threonine effects on performance, small intestine morphology and Salmonella spp. counts in Salmonella Enteritidis-challenged birds. Methods and Results: One-day-old chicks (1d) were distributed into five treatments: nonchallenged animals fed basal diet (RB-0), animals fed basal diet and infected with Salmonella Enteritidis (RB-I), animals fed high level of threonine and infected (HT-I), birds fed basal diet with MOS and infected (MOS-I), birds fed high level of threonine and MOS and infected (HT+MOS-I). Birds were inoculated at 2d with Salmonella Enteritidis, except RB-0 birds. Chicks fed higher dietary threonine and MOS showed performance similar to RB-0 and intestinal morphology recovery at 8 dpi. Salmonella counts and the number of Salmonella-positive animals were lower in HT+MOS-I compared with other challenged groups. Conclusion: Mannan oligosaccharides and threonine act synergistically, resulting in improved intestinal environment and recovery after Salmonella inoculation. Significance and Impact of the Study: Nutritional approaches may be useful to prevent Salmonella infection in the first week and putative carcass contamination at slaughter. This is the first report on the possible synergistic effect of mannan oligosaccharides and threonine, and further studies should be performed including performance, microbiota evaluation, composition of intestinal mucins and immune assessment. © 2012 The Society for Applied Microbiology.

Utilização de teste sorológico ELISA para a detecção de bovinos naturalmente infectados por Taenia saginata

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Performance, survivability and carcass traits of crossbred lambs from five paternal breeds with local hair breed Santa Inês ewes

The present study aimed to evaluate the performance, survivability and carcass traits of crossbred lambs. Data from 299 lambs born to 209 ewes were used. The dams were from a local hair breed (Santa Inês) and five breeds of sires were used: Dorper (DR), Ile de France (IF), Hampshire Down (HD), Texel (TX) and Santa Inês (SI). The lambs were weighed at birth, weaning and slaughter. Fasting body weight, skin thickness, hot and cold carcass weight, carcass yield and carcass length were measured at slaughter. Carcasses were separated into commercial cuts: neck, shoulder, rib, belly, loin and leg. Leg length and circumference were measured. Analyses of variances using MIXED procedure in SAS® were carried out for weights and carcass traits. Factor, discriminant and canonical analysis were carried out. Mortality data of animals from birth until slaughter was analyzed using logistic regression. The HD animals had the highest mortality rate. TX lambs had similar growth rate and survivability compared to DR and IF and had better carcass traits than these genetic groups. Therefore, this breed can be used as paternal breed to crossbreeding with Santa Inês dams. Santa Inês animals did not differ in growth from birth until slaughter compared to crossbred animals, which highlights the potential of this naturalized breed for meat production. Moreover, there is a great variability inside this breed for carcass and growth traits which may undergo great improvement through selection programs. © 2013 Elsevier B.V.

Predicción de ecuaciones para el porcentaje de grasa a partir de circunferencias corporales en niños pre-púberes

Introduction: The analysis of body composition through direct and indirect methods allows the study of the various components of the human body, becoming the central hub for assessing nutritional status. Objective: The objective of the study was to develop equations for predicting body fat% from circumferential body arm, waist and calf and propose percentiles to diagnose the nutritional status of school children of both sexes aged 4-10 years. Methods: We selected intentionally (non-probabilistic) 515 children, 261 children and 254 being girls belonging to Program interaction and development of children and adolescents from the State University of Campinas (Sao Paulo, Brazil). Anthropometric variables were evaluated for weight, height, triceps and subscapular skinfolds and body circumferences of arm, waist and calf, and the% fat determined by the equation proposed by Boileau, Lohman and Slaughter (1985). Through regression method 2 were generated equations to predict the percentage of fat from the body circumferences, the equations 1 and 2 were validated by cross validation method. Results: The equations showed high predictive values ranging with a R2 = 64-69%. In cross validation between the criterion and the regression equation proposed no significant difference (p > 0.05) and there was a high level of agreement to a 95% CI. Conclusion: It is concluded that the proposals are validated and shown as an alternative to assess the percentage of fat in school children of both sexes aged 4-10 years in the region of Campinas, SP (Brazil).

Parâmetros genéticos de características de carcaça e de crescimento de bovinos da raça Nelore

The objectives of this study were to estimate genetic parameters involving yearling weight (Ps), carcass weight (Pc), hip height (Ag) and the scores of conformation (C), precocity (P) and musculature (M) and carcass yield (Rd) and finishing score (Ac) in Nellore cattle in order to define criteria for selection in this breed. The data of the 20 732 animals were obtained from Agrope-cuária Jacarezinho, SP. Data were analyzed by restricted maximum likelihood using animal model multi-trait analysis, which included fixed effects of contemporary groups (animals born at the same month and slaughtered on the same day) and the covariate age at slaughter (linear) for carcass traits, and contemporary groups (animals of the same farm, age, sex and management group at weaning and yearling) and yearling age (linear) for growth and as random, the additive effects and residual effects. Estimates ranged from 0.13 (Ac and Rd) to 0.36 (Ag) for heritability and from -0.59 ± 0.62 (Rd with Ac) to 0.71 ± 0.17 (Pc with C) for genetic correlations. Selection for Pc, C, P, M, Ag or Ps may be efficient because their heritability estimates are of magnitude moderate. Selection for Ps and C can favor heavier Pc, considering their positive and high genetic correlation.

Expression of genes related to quality of Longissimus dorsi muscle meat in Nellore (Bos indicus) and Canchim (5/8 Bos taurus×3/8 Bos indicus) cattle

This study was performed to compare CAPN1, CAPN2, CAST, TG, DGAT1 and LEP gene expressions and correlate them with meat quality traits in two genetic groups (Nellore and Canchim) in order to assess their expression profile and use their expression profile as genetic markers. We analyzed 30 young bulls (1. year old), 15 of each genetic group. Samples of the Longissimus dorsi muscle were collected for analysis of: total lipids (TL) and meat tenderness measured as Warner-Bratzler shear force (SF) and myofibrillar fragmentation (MFI) at day of slaughter and 7. days of aging. Gene expression profiles were obtained via RT-qPCR. TL and MFI showed differences between breeds, higher MFI in Canchim and higher TL in Nellore. Calpains showed no differential expression between groups, as did DGAT1, TG, and LEP. CAST was expressed more in the Nellore cattle. The only significant within-breed correlation (0.79) between gene expression and meat traits was found for DGAT1 and MFI in Canchim breed. Although the number of animals used in this study was small, the results indicate that the increased expression of CAST in Nellore may reflect tougher meat, but the lack of correlations with the meat traits indicates it is not a promising genetic marker. © 2013 Elsevier Ltd.

Ocorrência de Listeria spp. e de Listeria monocytogenes, em um matadouro-frigorífico de bovinos do estado de São Paulo

We evaluated the presence of Listeria spp. and Listeria monocytogenes in environmental samples by means of swabs collected the bovine slaughter plant enabled to export, located in the state of Sao Paulo, Brazil. After the pre-enrichment at 30±1°C for 22 to 26h the samples were analyzed using the BAX System Listeria. Those positive for Listeria spp. were submitted a second PCR reaction to confirm the presence of Listeria monocytogenes. From 411 environmental samples analyzed, 62 (15.1%) were positive for Listeria spp. and 21 (5.1%) for Listeria monocytogenes, which showed their persistence in the slaughter plant. There were no statistical differences between the rainy and dry periods and between areas sampled, although it has been found between sectors. The floor surface and the sector cuts have higher rates of positivity.

Association of the Leptin Gene with Carcass Characteristics in Nellore Cattle

Advances in DNA technology have created biotechnological tools that can be used in animal selection and new strategies for increasing herd productivity and quality. The objective of the present work was to associate the genotypes of leptin gene exon 2 polymorphisms with productive traits in Nellore cattle. Blood was collected from Nellore males and PCR-RFLP reactions were performed with the restriction enzymes ClaI and Kpn2I. The gene frequencies resulting from digestion by ClaI were 0.60 and 0.40 for allele A and T, respectively; the genotypic frequencies were AA = 0.20 and AT = 0.80. The gene frequencies from digestion by Kpn2I were 0.81 for allele C and 0.194 for allele T; the genotypic frequencies were CC = 0.62 and CT = 0.38. The populations in both cases were not in Hardy-Weinberg equilibrium (p > 0.05), and the TT genotype was not found. Significant associations were noted between leptin gene exon 2 polymorphisms and five productive traits in Nellore cattle: carcass fat distribution, the intensity of red muscle coloration, pH, marbling, and post-slaughter fat thickness. © 2013 Copyright Taylor and Francis Group, LLC.

Meat and carcass traits of the red-winged tinamou (Rhynchotus rufescens)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects on performance and carcass and meat quality attributes following immunocastration with the gonadotropin releasing factor vaccine bopriva or surgical castration of bos indicus bulls raised on pasture in brazil

Bos indicus bulls 20. months of age grazed on pasture in Minas Gerais, Brazil either received 2 doses of the GnRF vaccine Bopriva at d0 and d91 (group IC, n. =. 144) or were surgically castrated on d91 (group SC, n. =. 144). Slaughter on d280, was 27. weeks after castration. Adverse safety issues in 8% of group SC bulls following surgery contrasted with 0% in group IC bulls. At d105 testosterone levels were suppressed to similar levels in both groups. Importantly, group IC bulls had higher live weight, hot carcass weight, ADG (P<. 0.005) and dressing percentage (P<. 0.0001) compared to group SC animals. There were no negative effects on carcass or meat quality traits, thus immunocastration was concluded to offer a safe and effective method that provides production gains, and improves animal welfare in Bos indicus beef bulls without impacting meat and carcass quality. © 2013 Elsevier Ltd.

Biochemical Profile of Amniotic and Allantoic Fluid During Different Gestational Phases in Mares

Fetal fluids have different vital functions that sustain both pregnancy and normal parturition. The biochemical composition of amniotic fluid during gestation is not well established; thus the purpose of the present study was to determine the biochemical profile of both amniotic and allantoic fluids from mares during initial, mid, and latter third phases of pregnancy. Samples were collected after slaughter, using allantocentesis and amniocentesis. Sixty samples of fetal fluids were analyzed. Alkaline phosphatase (AP), glucose, total protein (TP), urea, creatinine, Ca, chloride (Cl), Na, and K concentrations were measured using commercially available kits. The AP concentration in amniotic fluid was higher than that in allantoic fluid during the three gestational phases (P < .05). There were no differences between glucose mean values of allantoic and those of amniotic fluids (P < .05). However, glucose values were higher in the allantoic fluid in the last trimester of pregnancy. TP was higher in the amniotic fluid than in allantoic fluid (P < .05). Urea values varied among the phases; however, there were no differences between the amniotic and allantoic fluid values (P > .05). Creatinine values were higher in allantoic fluid (P < .05). Na and Cl concentrations were higher in amniotic fluid (P < .05). However, Ca and K concentrations were higher in the allantoic fluid. © 2013 Elsevier Inc. All rights reserved.

Avaliação da qualidade de efluentes na criação de rã-touro (Lithobates catesbeianus)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência da adição in vivo de vitamina E e de métodos de abate nos atributos de qualidade de filés de tilápia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Glicerina na alimentação de cordeiros 1/2 Dorper 1/2 Santa Inês: consumo, digestibilidade, desempenho, características quantitativas da carcaça e qualitativas da carne

Pós-graduação em Zootecnia - FCAV