A microbial muramidase improves growth performance and reduces inflammatory cell infiltration in the intestine of broilers chickens under Eimeria and Clostridium perfringens challenge.

The objective of the present studies was to evaluate muramidase (MUR) supplementation in broilers under Eimeria and/or Clostridium perfringens challenge. For this, 2 experiments were conducted. Experiment 1. A total of 256 one-day old male Cobb 500 chicks were placed in battery cages in a completely randomized design, with 5 treatment groups, 7 replicate cages per treatment and 8 birds per cage. The treatments were: nonchallenged control (NC), challenged control (CC), CC + MUR at 25,000 or 35,000 LSU(F)/kg, and CC + Enramycin at 10 ppm (positive control-PC). Challenge consisted of 15× the recommended dose of coccidiosis vaccine at placement, and Clostridium perfringens (108 CFU/bird) inoculation at 10, 11, and 12 d. Macro and microscopic evaluation, immunohistochemistry, and gene expression were evaluated at 7, 14, 21, and 28 d of age. Experiment 2. A total of 1,120 one-day old male Cobb 500 chicks were placed in floor pens with fresh litter in a completely randomized design, with 4 treatment groups, 8 replicate pens per treatment, and 35 birds per pen. The treatments were: Control, supplementation of MUR at 25,000 or 45,000 LSU(F)/kg, and a positive control (basal diet plus Enramycin). At 10, 11, and 12 d of the experiment all the birds were inoculated by oral gavage with a fresh broth culture of a field isolate Clostridium perfringens (0.5 mL containing 106 CFU/bird). It was observed that in Experiment 1 MUR supplementation reduced the infiltration of macrophages and CD8+ lymphocytes in the liver and ileum of infected birds, downregulated IL-8 and upregulated IL-10 expression. In Experiment 2, MUR linearly improved the growth performance of the birds, increased breast meat yield, and improved absorption capacity. MUR supplementation elicited an anti-inflammatory response in birds undergoing a NE challenge model that may explain the improved growth performance of supplemented birds.

Quantifying the effect of coccidiosis on broiler performance and infection outcomes in the presence and absence of control methods.

A systematic review and meta-analysis was conducted to investigate the role of Eimeria species, dose and inoculation time, on performance and infection outcomes of different broiler strains infected for different study durations. The meta-analysis addressed E. acervulina, E. maxima, E. tenella, and mixed species infections, and involved data from 72 peer-reviewed articles, corresponding to 521 treatments performed on 20,756 broilers. A secondary objective was to investigate the effects of synthetic anticoccidials, ionophores, and vaccination against Eimeria on the above outcomes. Performance during infection was scaled (%) to that of the uninfected birds. Infection reduced scaled ADFI and ADG (P < 0.001) and increased feed conversion ratio (FCR; P < 0.05); there was a significant interaction between dose and species on scaled ADFI and ADG, suggesting that different species affected these variables to different extents (P < 0.001). There was a tendency for an interaction between dose and broiler strain on scaled ADFI (P = 0.079), and a significant interaction between these variables on scaled ADG (P < 0.01). A tendency for an interaction between oocyst dose and Eimeria species (P = 0.067) on maximum number of oocysts excreted was observed. Lesion scores were significantly affected by dose, species, and their interaction (P < 0.05), the latter caused by an increase in the lesion scores during E. maxima and E. tenella infections. Control methods significantly affected scaled ADG and FCR (P < 0.05) and there was an interaction between dose and control methods on ADFI (P < 0.001). Synthetic anticoccidial use improved scaled ADG (P < 0.01), whereas ionophores improved FCR compared with untreated birds (P < 0.01). An interaction between dose and control method on scaled ADFI was caused by the higher ADFI of vaccinated compared to untreated birds, as dose increased. There was a significant effect of control methods on lesion scores (P < 0.01). All findings advance our understanding of the factors that influence the impact of coccidiosis and its controls in broilers.

Enzymatic programs for broilers

Two trials were conducted on floor pens to evaluate the performance of broilers fed with diets contained different carbohydrases enzyme programs at different ages. Trial 1- The body weight gain (BWG) was affected by the Negative Control (NC) treatment (P<0.05). However, when the birds were fed with the NC diet + Amilase (AMY)+Xilanase (XYL), the BWG improved and reached the same level as the Positive Control (PC). Trial 2- The birds received enzymes supplementation in the total phase and others only in the grower phase.The ME reduction by 120 kcal/kg increased the feed conversion ratio (FCR) (P<0.05) when compared to PC and none of the enzyme programs was able to recover the performance. It can be concluded that it is possible to supplement with AMY during the role period of broiler chicken life or use an enzymatic program with AMY or AMY+XYL only in the grower phase.

Para avaliar o desempenho de frangos de corte alimentados com rações com diferentes programas de enzimas carboidrases, foram realizados dois experimentos. No experimento 1 as aves receberam suplementação de enzimas apenas na fase de crescimento foi observado redução no ganho de peso (GP) daqueles alimentados com a ração Controle Negativo (CN) ou seja, ração com redução de 120 kcal/kg. No entanto, quando os frangos receberam a ração CN + Amilase (AMI) + Xilanase (XIL) o GP foi semelhante encontrado no Controle Positivo (CP). No Experimento 2, algumas aves tiveram enzimas em todo período de criação e outras tiveram apenas na fase de crescimento. O tratamento CN apresentou pior conversão alimentar que o CP. Pode-se concluir que é possível suplementar com AMI todo o período de criação das aves ou utilizar um programa enzimático com AMI ou AMI + XIL somente na fase de crescimento, sem prejuízo ao desempenho das aves.

Níveis vitamínicos para frangos de corte: [revisão] / Vitamin levels for broiler: [review]

As vitaminas são micronutrientes que participam de inúmeros processos metabólicos do organismo, sendo, portanto, essenciais para ótima saúde e desempenho do animal. Poucos trabalhos foram realizados nos últimos anos para estimar os melhores níveis de vitaminas para frangos, havendo grande variação entre os níveis empregados comercialmente. Sendo assim, o objetivo deste trabalho é apresentar os conceitos atuais na avaliação das exigências de vitaminas para frangos e os níveis sugeridos pela indústria e pelo meio científico. A maioria dos níveis recomendados pelo NRC (1994) foi baseada em trabalhos antigos, realizados em condições controladas e considerando os níveis mínimos para evitar sinais de deficiência, não avaliando o melhor desempenho nas condições de desafio encontradas a campo. Além disso, as linhagens atuais apresentam maior taxa de crescimento e produção, resultando em maior necessidade nutricional para expressar seu potencial genético. Atualmente, além dos índices zootécnicos, têm se avaliado outros parâmetros na determinação das exigências de vitaminas, tais como imunidade, bem-estar e características da carcaça. Os níveis vitamínicos empregados comercialmente são geralmente superiores aos preconizados pelo NRC (1994), sendo que os níveis das lipossolúveis podem superar até 25 vezes as recomendações e os das hidrossolúveis até cinco vezes. O uso de maiores níveis de vitaminas na dieta de frangos resulta em maior desempenho produtivo e qualidade da carne.

Vitamins are micronutrients that participe in many metabolic processes of the organism, being essential to animal health and performance. There has been little research conducted over the last years on estimating the best vitamin levels for broilers, having great variation on comercial levels. The objective of this study was to present the actual concepts of the evaluation of vitamin requirements for broiler and the levels recomendated by industry and research centers. The major levels recomendated by NRC (1994) were based on former studies, with controled conditions and considering minimal levels to avoid deficiency signs, not evaluating the best performance on the challenge conditions found in field. Furthermore, modern strains presents greater growth rate and production, resulting in higher nutritional requirements to express their genetical potential. Nowadays, besides zootecnical parameters, it had been evaluating other parameters to determine vitamin requirements, as imunity, well being and carcass characteristics. Comercial vitamin levels used are generally superior than the suggested by NRC (1994), and the liposolubles levels may be higher than 25 times the recomendations and hydrosolubles five times higher. The use of higher vitamin levels in brolier diet results in greater productive performance and meat quality.