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)

Diet formulation techniques and lysine requirements of 1- to 22-day-old broilers

Two experiments were carried out to compare two techniques (amino acid supplementation and dilution) for formulating experimental diets for pre-starter (1 to 8 days) and starter (8 to 22 days) broiler chicks and to estimate digestible lysine requirements using the dose-response method. In each experiment, 1,200 male Cobb 500 chickens were randomly distributed according to a 5x2 factorial arrangement (lysine level x formulation technique) with six replicates of 20 birds each. For the supplemented diet, a basal diet was formulated to meet the nutritional requirements, then L-lysine HCl was added to achieve digestible lysine levels of 0.975, 1.082, 1.189, 1.296 and 1.403% in the pre-starter diets and 0.840, 0.932, 1.024, 1.116 and 1.208% in the starter diets. For the diluted diet, a diet high in crude protein (CP) and relatively low in lysine was formulated and to which was added a protein-free diet until lysine levels were similar to those described above for the supplemented diet. The results suggest that the dilution technique favored the performance potential and better met lysine requirements compared with the supplementation technique. Lysine levels required for optimal feed conversion ratio of broilers during the pre-starter and starter phases were estimated at 1.361 and 1.187%, which are equivalent to lysine intake of 0.340 and 0.797 g/day, respectively.(AU)

Eficiência de uma fitase bacteriana na liberação de fósforo fítico em dietas de frangos de corte / Efficiency of a bacterial phytase to release phytate phosphorus in broiler chicken diets

Foi avaliada a eficiência de uma fitase (FT) bacteriana na liberação de fósforo fítico utilizando-se curvas de calibração para características ósseas e de desempenho em frangos de corte. O delineamento experimental foi inteiramente ao acaso, com seis tratamentos e seis repetições até 28 dias de idade. O tratamento-controle foi uma dieta à base de milho e farelo de soja deficiente em fósforo (P). Dois tratamentos corresponderam às dietas basais acrescidas de P suplementar, 0,05 por cento e 0,10 por cento, e os outros à dieta basal com 66, 99 e 131 FTU/kg de ração. A curva padrão é definida pelo efeito da adição de P suplementar consumido sobre características ósseas e de desempenho, e os resultados dos tratamentos com fitase são confrontados com a curva para cálculo de P liberado. A adição de P suplementar influenciou o ganho de peso, o peso vivo e o consumo de ração de forma quadrática, bem como miligramas de cinzas ósseas de forma linear. A curva padrão adotada foi da variável miligramas de cinzas ósseas, pois a resposta linear melhor descreve a curva. As inclusões de 66, 99 e 131 FTU/kg liberaram, respectivamente, 0,048 por cento, 0,049 por cento e 0,062 por cento de P. A fitase bacteriana é eficiente na liberação de fósforo fítico e possui viabilidade econômica.(AU)

The objective was to determine the efficiency of a bacterial phytase to release phytate phosphorus using calibration curves for performance and bone characteristics in broiler chickens. A completely randomized design with 6 treatments and 6 replicates was used in an experiment with chickens from 1 to 28 days of age. The control treatment was a diet based on corn and soybean meal deficient in phosphorus. Two treatments consisted of the basal diet supplemented with additional phosphorus (0.05 percent and 0.10 percent), and the other treatments received 66, 99 and 131 FTU/kg of feed. The standard curves represented the effect of the levels of additional P intake on performance and bone variables. Then, the responses of the phytase treatments were compared to the standard curves to calculate the P released. The increasing levels of supplemental P had a quadratic effect on weight gain, live weight and feed intake, and linear effect on mg of bone ash. The standard curve elected was mg of bone ash because linear response better represents the curve. Inclusion of 66, 99 and 131 FTU/kg released 0.048 percent, 0.049 percent and 0.062 percent. The bacterial phytase is efficient in releasing phytate, which may be of economical significance.(AU)

Valor nutricional do milho termicamente processado, usado na ração pré-inicial para frangos de corte / Nutritional value of heat processed corn in formulating broiler pre-starter diet

Foram conduzidos um ensaio de metabolismo para determinar o valor nutricional do milho termicamente processado (MP) e não-processado (MNP) e outro de desempenho para comparar o uso desses alimentos em dietas pré-iniciais para frangos de corte. Não foram observadas diferenças entre a digestibilidade da matéria seca (MS), do extrato etéreo, da proteína bruta e do amido e valores de energia metabolizável aparente dos tipos de milho avaliados. A energia metabolizável aparente corrigida do MP (3.537kcal/kg de MS) foi maior (P<0,05) que a determinada para o MNP (3.411kcal/kg de MS). No ensaio de desempenho, os tratamentos foram: T1- dieta formulada com MNP; T2 - dieta formulada com MP; e T3 - dieta T1, com substituição isométrica do MNP por MP. Na primeira semana, as aves alimentadas com MP (T2) apresentaram maior consumo (P<0,05) e pior conversão (P<0,05) em relação às alimentadas com MNP (T1). A substituição isométrica do MNP por MP não influenciou no desempenho das aves. No período de 1 a 42 dias, os tratamentos não influenciaram o desempenho dos frangos.(AU)

A digestibility trial was carried out to evaluate the nutrient digestibility of heat-processed corn (PC) and not processed corn (NPC). A trial was also carried out to evaluate the effect of PC and NPC in pre-starter diet on broiler performance from 1 to 42 days of age. The dry matter (DM), ether extract, crude protein and starch digestibilities and apparent metabolizable energy for PC were similar (P>0.05) to those observed for NPC. The corrected apparent metabolizable energy of PC (3,537kcal/kg of DM) was higher than NPC (3,411kcal/kg of DM). The treatments in the performance trial were T1- diet formulated with NPC, T2- diet formulated with PC, and T3 - isometric substitution of NPC for PC in T1 diet. The broiler fed on NRC diets showed lower feed consumption and weight gain:feed consumption ratio from 1 to 7 days of age than broiler fed on PC diets. The isometric substitution of NPC for PC in the pre-starter diet did not affect the performance of birds. No treatment effect on broiler performance from 1 to 42 days of age was also observed.(AU)

QUALITY OF EGGS FROM COMMERCIAL LAYERS STORED FOR DIFFERENT TIMES AND ENVIRONMENT CONDITIONS. / QUALIDADE DE OVOS COMERCIAIS PROVENIENTES DE POEDEIRAS COMERCIAIS ARMAZENADOS SOB DIFERENTES TEMPOS E CONDIÇÕES DE AMBIENTES.

A completely randomized factorial 4 x 6 x 2 design was used (four commercial strains – Hy-Linewhite and brown and Hisex white and brown, six storage times (ST) - 0, 7, 14, 21, 28, and 35 days and two storage conditions – environment with and without control). The studied variables were: % egg weight loss (WL), Haugh units (UH), specific gravity (EG), % yolk, and % albumen. As the ST increases a linear fall occurs in HU and SG and WL of the eggs, which was ascribed to the water loss of the albumen, since its proportion decreased linearly with time of storage. A linear increase occurred in the % of yolk while the peel proportion was slightly changed. The ST promotes weight loss and changes the internal quality, which was documented when eggs were stored in uncontrolled environments.   KEYS-WORDS: Eggs. Internal quality. Storage. Strains. Temperature.

O delineamento experimental foi inteiramente casualizado em esquema fatorial 4 x 6 x 2 (quatro linhagens – Hy-Line branca e marrom; e Hisex branca e marrom, seis tempos de armazenamento (TA) – 0,7 14, 21, 28 e 35 dias e duas condições de armazenamento – ambiente sem controle e controlado). As variáveis estudadas foram: perda de peso em porcentagem (PP), unidades Haugh (UH), gravidade específica (GE), porcentagem de gema (%G) e albúmen (%A). À medida que o TA aumentou ocorreu queda na UH e na GE e PP linear dos ovos promovida pela perda de água do albúmen, pois a proporção do mesmo diminuiu com o TA. Ocorreu um aumento linear na %G. O TA promoveu perda de peso e alterou a qualidade interna evidenciada quando os ovos foram armazenados em ambientes não controlados. PALAVRAS-CHAVES: Ambiente. Armazenamento. Linhagens. Avos. Qualidade interna.

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

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.