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 x 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.(AU)

EFFECT OF LIGHTING PROGRAMS ON BROILER CHICKENS PERFORMANCE, CARCASS YIELD AND PARTS YIELD. / EFEITO DE PROGRAMAS DE LUZ SOBRE O DESEMPENHO E RENDIMENTO DE CARCAÇA, CORTES COMERCIAIS E VÍSCERAS COMESTÍVEIS DE FRANGOS DE CORTE.

  An experiment was conducted to determine the effects of two lighting programs on performance, carcass yield and parts yield of broiler chickens. Nine-hundred-sixty Cobb male and female broiler chicks were used and distributed in a completely randomized design with 2 x 2 factorial arrangement (two sexes and two lighting programs: - increasing light: 1 to 14 days, 24L:0D; 15 to 21 days, 16L:8D; 22 to 29 days, 18L:6D; 30 to 40 days, 20L:4D and 41 to 49 days, 23L:1D; - continuous light: 23L:1D to 1 to 49 days of age) with four treatments and six replicates of 40 birds. In the starter phase, birds raised on increasing light program showed lower body weight gain and feed intake as compared to those submitted to continuous light program. However, in the total period of rearing no significant differences between treatments were observed. Carcass yield and parts yield showed no standard profile. In conclusion, a compensatory gain in the broiler chickens reared on increasing light program was observed.     KEY-WORDS: Broiler chickens. Lighting programs. Performance. Sex. Yield.    

EFFECT OF ORGANIC ACID AND PLANT EXTRACT ON PERFORMANCE AND QUALITY EGG OF LAYING HENS / EFEITO DE ACIDIFICANTES E EXTRATOS VEGETAIS SOBRE O DESEMPENHO E QUALIDADE DE OVOS DE POEDEIRAS COMERCIAIS

                The trial was conducted to evaluate the best level of organic acid inclusion and effect of plant extracts on the performance parameters and quality of eggs of laying. Lohmann LSL laying hem strain (256) at 40 weeks of age were distributed in a blocks in factorial design 4 x 2 (four acid levels and two levels of plant extract) with two blocks, two replications for each treatment in the block with eight birds for experimental unit. The birds were distributed in the blocks based in their weight. The treatments were: control (without additive), 200g/t of acid, 400g/t acid, 600g/t acid, 150 g/t of plant extract, 200g/t of acid + 150g/t of plant extract, 400g/t of acid + 150g/t of plant extract and 600g/t acid + 150g/t of plant extract. The experimental period was 84 days divided in three cycles of 28 days each. The association of organic acids with vegetal extract promoted highest percentage of production and feed conversion/twelve eggs. However, these additives did not affect the feed intake, Haugh units and specific gravity of eggs of the commercial laying hens in the end of production cycle. The inclusion of 400 g/t of acids plus 150 g/t extract can improved egg production.           KEY - WORDS:      

Essa pesquisa foi conduzida com o objetivo verificar o melhor nível de inclusão e o efeito de ácidos orgânicos e extratos vegetais sobre os parâmetros de desempenho e qualidade de ovos de poedeiras comerciais. Utilizou-se 256 poedeiras da linhagem Lohmann LSL com 40 semanas de idade, distribuídas em delineamento de blocos ao acaso no esquema fatorial 4 x 2 (quatro níveis de ácido e dois níveis de extrato vegetal) com dois blocos, duas repetições por tratamento em cada bloco e oito aves por unidade experimental. As aves foram distribuídas nos blocos em função do peso. Os tratamentos foram: controle (sem aditivo), 200g/t de ácido, 400g/t ácido, 600g/t ácido, 150g/t de extrato vegetal, 200g/t de ácido + 150g/t de extrato vegetal, 400g/t de ácido + 150g/t de extrato vegetal e 600g/t ácido + 150g/t de extrato vegetal. O período de avaliação foi de 84 dias divididos em três ciclos de 28 dias. A associação do acidificante com o extrato vegetal promoveu maior porcentagem de postura e conversão alimentar por dúzia de ovos. No entanto, a administração isolada ou asso