Uso do ácido orgânico (ácido fumárico) nas rações de frangos de corte

This experiment was carried out to evaluate the effect of the addition of fumaric acid to broiler diet on birds performance. One thousand and eighty Hubbard day-old broiler chicks were alloted in a randomized block design, six treatments with two replicates of males, and four replicates of females. Three basal diets were formulated to meet the nutritional requirements in each growing phase: from 1 to 21 days, 21 to 37 days and 37 to 45 days. Treatments consisted first in the addition of growth promoter to 0.75 and 1.0%, of fumaric acid. The group treated without of both growth promoter and fumaric acid presented a higher intake and a smaller feed:gain ratio in relation to the fumaric acid treated groups. However, there were no differences among groups treated with growth promoter and fumaric acid. The contrasts did not show any difference among weight gain, carcass yield and abdominal fat. The addition of fumaric acid levels to the diets promoted reduction of feed intake, without any effect on weight gain, improving, therefore, the feed/gain ratio. A digestibility experiment was carried out, using 30 Hy-Line roosters, to determine apparent metabolyzed energy (AME), corrected by nitrogen of the diets containing 0.0, 0.5 and 1.0% of the acid. An increase on the AME of the diets was observed with fumaric acid addition.

Efeito dos níveis de energia da ração sobre o desempenho e teor de gordura na carcaça de frangos de corte

It was studied the effect of energy levels in the diet, obtained from vegetal oil inclusion, on the performance, diet cost per kilogram of broiler and fat content of the carcass, There were used 4,800 broiler chicks, 2,400 males and 2,400 females, and they were distributed in six treatment (energy levels in kcal ME/kg of diet) in three different phases: start diet from one to 20 days of age: A - 2930, B - 2980, C - 3030, D - 3080, E - 3130, F - 3180, growth diet from 21 to 40 days: A - 2980, B - 3030, C - 3050, D - 3130, E - 3150, F - 3230, finishing diet from 41 to 45 days of age: A - 3030, B - 3080, C - 3130,, D - 3180, E - 3230, F - 3280. The protein content was 22, 20 and 18% in each phase, respectively, There were evaluated the feed intake, energy intake, protein intake, weight gain, feed conversion mortality, diet cost per kg/bw. Sixty broilers were slaughtered, five males and five females per treatment, randomly chosen to determine the carcass composition considering the dry matter content, lipids content and protein content, total fat in carcass and fat per kilogram of broiler. The data were submitted to variance analysis and the means were compared using SNK. The broilers fed with medium and low levels of dietary energy showed the highest weight gain. At energy levels of the treatment D in the three phases, the lowest cost per kilogram of broiler was obtained. The females presented the highest fat content per kilogram of broiler produced.

Níveis de cloreto de sódio em rações para frangos de corte

A trial was carried out using 1,000 day-old chicks to evaluate levels of NaCl (0.30, 0.45, 0.60, 0.75 and 0.90%) in diets. Water and feeding with 20.1 and 18.2% CP, 2, 900 and 2,950 kcal/kg ME respectively for initial and finishing phases were offered ad libitum. High levels of NaCl (0.60, 0.75 and 0.90%) increased the water intake and water:feed ratio during the first 21 days (P<0.05). Whitin the period of 21-42 days only water intake increased (P<0.05). Body weight, feed and water intake, mortality were higher (P<0.05)for males. High levels of NaCl (0.60, 0.75 and 0.90%) increased (P<0.05) body weight, water intake, water:feed ratio and moist litter during the trial. The supplementation of high levels of NaCl increased performance, bur implied in higher litter moisture.

Desempenho de frangos de corte de 1 a 21 dias de idade alimentados com rações contendo extrato de leveduras e prebiótico e criados em diferentes temperaturas

The performance of broilers reared at different temperatures and fed diet with or without yeast extract and/or prebiotic in the starter phase was evaluated. One thousand, four hundred and forty 1-d male Cobb-500 (R) were reared at different climatic chambers. The diets with or without yeast extract or prebiotic were fed only in the starter phase (1 to 7 days), and from the 8(th) day on all broiler were fed the same commercial diet. It was used a complete randomized experimental design, as a 3 x 2 x 2 factorial arrangement, with 3 rearing temperatures (high 34 +/- 1 degrees C, control 32 +/- 2 degrees C and low 27 +/- 2 degrees C), 2 yeast extract level (with or without) and 2 prebiotic level (with or without). High and low temperatures decreased the performance of brids at 7 and 21 days old. The inclusion of prebiotic in the pre-starter phase increased weight gain of birds under low temperature at 21 days old and the viability until 21 days old. The inclusion of yeast extract increase feed conversion at 21 days old.

Substituição do farelo de soja pelo de guandu na alimentação de frangos de corte

The objective of this work was to evaluate the nutritive value of pigeon pea meal (PPM) with methionine substituting soybean meal (SM) in diets for 1-28 day-old broiler chicks. The experimental design was that of random blocks, in a 3 × 3 factorial scheme with three substitution levels - 15,30 and 45% - and three methionine supplementation levels in relation to the requirements, that is: 100, 66 and 33%, with four repetitions. It was found that PPM treated for 20 minutes at 100°C substituted up to 30% of the SM, even without methionine supplementation, in relation to liveweight (p<0.01), to food conversion and to the efficiency of utilization of metabolizable energy and to protein (p<0.05). At the 66% level of methionine supplementation, the same results as for these parameters were obtained at all of the levels of substitution of SM by PPM. The 30% or 45% substitution of SM protein by that of PPM affected (p<0.01) the efficiency of methionine utilization. The sulphur amino acid utilization efficiency was affected (p<0.01) beginning at 66% methionine supplementation in the diets.

Efeitos da densidade populacional e da energia da dieta sobre o desempenho de frangos de corte

The experiment was conducted to determine the effect of feeding three levels of energy (2800, 3000 and 3200 kcal ME/kg) in diets and two stocking densities (10 and 22 birds/m 2) on broilers performance. The experimental design was randomized blocks in a 3 × 2 × 2 factorial arrangement with four replication per treatment. The factors studied were levels of energy in the diet, population density, and sex. The birds were killed at 42 days of age. The data indicate that increasing energy levels in the diets of broilers, 1 to 42 days of age, reduced feed intake, improved feed conversion, and increased the amount of abdominal fat, energy intake, and weight gain without affecting carcass yield. There was no significant effect of diet on the live weight production of broilers produced per area of floorspace or on mortality. The higher values for carcass yield were obtained for birds raised under the higher population density and for males in comparison to females. With the exception of the undesirable elevation in the amount of abdominal fat, the increase in the level of energy in the diets resulted, in general, in an improvement in the performance of the broilers independent of the population density. However, the response to the amount of energy in the diet was similar for both population densities.

Efeitos de diferentes densidades populacionais nas estações fria e quente do ano sobre o desempenho de frangos de corte

The objective of this study was to evaluate the performance of broilers reared under different population densities in the cold and hot seasons of the year. Two identical experiments were conducted, one during the winter for 49 days, and the other during the summer where the chicks were slaughtered at 42 days of age. Commercial Hubbard broiler-type chicks were distributed in a randomized block design in a 4 × 2 factorial arrangement with population densities of 10, 14, 18, and 22 birds/m 2, by sex, and with four replications. Feed intake was reduced with a progressive decrease of available space for the chicks, and it resulted in a linear decrease in weight gain. However, there was a linear increase in the live weight of broilers in kilograms per area of floor space, proportional to the increase of population density, without effect on the viability. The progressive increment in the population density reduced the observed feed/gain ratio during the total winter rearing period for both sexes. There was no effect of population density on this characteristic during the hot season of the year. Population density did not affect the carcass yield of chicks during the summer. However, there was a linear increase on carcass yield with an increase in population density in the winter. The males, at the age slaughtered, had higher weights, feed intakes, and better feed/gain ratios, and lower abdominal fat and higher live weight production in kilograms per floor area than females. However, the viable index for the males was lower. From the results obtained, there was a linear increase in the liveweight of broilers in kilograms per floor area, making it possible to rear broilers under higher population densities, independent of the season of the year, as well as the occurrence of a decrease in feed intake and weight gain of the chicks with a decrease of available space.

Efeito do período de jejum na fase final de criação de frangos de corte machos sobre desempenho e mortalidade

The objective of this work was to evaluate effect of fasting period in the last growing phase on performance and mortality of male broilers. Two thousand one-day old male chicks were distributed in five randomized blocks according to a 4x2 factorial. (Four feeding programs (FP): ad libitum or one of three fasting schedules: 8-12, 12-16 and 8-16; and two strains (S): Ross or Hubbard-Peterson). Fifty birds were used per replicate. Birds were raised under identical feed and management conditions until day 42. During the experimental period (days 43-56), average temperature, relative humidity and temperature-humidity index (THI) recorded at day and at night were 29.4°C, 57.7 % and 78.1; and 22.0°C, 73.1% and 67.4, respectively. No SxP interaction was observed for all characteristics studied. At day 56, the Ross broilers showed higher mean weight (3104 g), weight gain, WG (3059 g), feed/ gain ratio, FC (2.22) and production factor, PF (213), than the Hubbard-Peterson birds (3011, 2967, 2.28 and 194, respectively). During the experimental period, the Ross broilers showed higher WG (831 g) and FC (3.40) than the Hubbard-Peterson ones (770 and 3.67, respectively). Birds submitted to the 8-12 h fast showed higher feed intake (2864 g) than those that fasted during the 8-16 period (2690). No effect of P on mortality was observed, either considering the overall period (days 1-56) or the experimental period (days 43-56). Fasting in the last phase of rearing not aided by other practices failed to decrease heat stress effects on performance and mortality of male broilers.

Uso da restrição alimentar quantitativa para diminuir a mortalidade de frangos de corte machos

The effect of feed restriction (0, 10, 20, 30, 40 and 50%) from 8 until 14 days post-hatching on performance, total mortality incidence and sudden death syndrome (SDS) rate was studied in male broilers during winter and summer.Ad libitum fed broilers had a better performance, but a higher total mortality rate (13.00% in winter, 3.67% in summer) and SDS (3.67% in winter, 0.67% in summer). All restricted groups had a lower mortality level in winter than the control group with a non linear response influenced by feed restriction. Birds submitted to 40% feed restriction showed the lowest mortality incidence (2.67%) followed by groups submitted to 30% (4.67%), 50% (5.33%) and 10% and 20% (7.67%) feed restriction. Birds fed ad libitum had the highest SDS incidence (3.67%, against .33, 1.00, .67, 1.33 and 1.33% at 10, 20, 30, 40, 50% feed restriction, respectively), but differences were not significant. In summer, incidences of total mortality and due to SDS were low and not influenced by feed restriction, either during the restrictive period itself (8 to 14 days) or during the total period of raising (1 to 49 days). In both seasons, the feed restricted birds showed compensatory gain only until three weeks post-restriction period. At 49 days, body weight and weight-gain were lower in feed restricted birds, but feed :gain ratio rate was improved. This resulted in better productivity index in winter, but not in summer. The feed restriction at 30 to 40% for seven days during the second week may decrease mortality in male broilers raised in winter without lowering productivity if the restriction is followed by at least three weeks of full feeding.

Efeito da seleção quanto ao peso corporal nas características reprodutivas em linhagens de frangos de corte

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito do Nível de Energia da Dieta e da Exposição Prévia ao Calor sobre a Respiração Mitocondrial do Músculo Cardíaco de Frangos de Corte

This work was conducted aiming to evaluate the effect of dietary energy level and the previous heat exposure on the respiratory activity of the mitochondria from the cardiac muscle of broiler chickens. It was used broiler chickens (Hubbard) from both sexes and fed with diet containing 2900 kcal ME/kg or 3200 kcal ME/kg. The birds were heat stressed (35°C/4h) in the 1 st, 21 st and 42 nd days of age. The respiratory activity of mitochondria from cardiac muscle was evaluated in a Gilson oxygraph, model 5/6, by using alpha-ceto-glutaric as substrate and the ADP (adenosine-di-phosphate) to stimulate the respiratory activity. There was not effect of dietary energy level and previous heat exposure on the respiratory activity of the mitochondria from cardiac muscle. However, the females presented higher respiratory activity than males. By reason of the low oxidative capability of the heart muscle fiber of the male broiler chickens, these could be more sensitive to cardiac disease than females.

Efeito da restrição alimentar inicial e da temperatura ambiente sobre o desenvolvimento de vísceras e ganho compensatório em frangos de corte

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

Desempenho e morfometria da mucosa de duodeno de frangos de corte alimentados com farelo de canola, durante o período inicial

A trial was carried to verify the effect of increasing levels (0, 10, 20, 30 and 40%) of canola meal in diets of broiler chickens on performance and mucous morphology, during the starting period (1 - 21 days). One thousand 1-d male chicks were assigned to a randomized experimental assay, with five treatments, four replicates and 50 birds per experimental unit. At the 1 st, 21 st and 41 st days, the birds and the rations were weighed. At the 21 st day, two birds of each experimental unit were sacrificed for collection of a duodenum segment to evaluate the intestinal morphometry. The results demonstrated that increasing levels of canola meal resulted in linear reduction on weight gain, weight and feed intake and worst feed conversion. During the growing period (21 to 41 days), when all birds received similar diet, average weight and weight gain decreased, as the canola meal levels increased, while feed conversion and feed intake were similar. Data regarding mucous morphology, submitted to the regression analysis, demonstrated that the crypt depth increased, as the canola meal levels increased. It is possible to include up to 20% of canola meal without damages on broiler performance and digestive tract.

Efeito do nível de energia metabolizável da dieta no desempenho e metabolismo energético de frangos de corte

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito da temperatura ambiente e da restrição alimentar protéica ou energética sobre o ganho de peso e crescimento ósseo de frangos de corte

The effect of protein or energy restriction during the second week post-hatching on body weight gain and femur development of broiler chickens reared at different environmental temperatures (18°C, 25°C and 33°C) was studied. From 1 to 7 days of age and after a restriction period broilers were fed on a control diet with 2850 kcal ME/kg and 20% crude protein. From 8 to 14 days of age, two groups of broilers were fed on restricted energy and protein diets with 2565kcal ME/kg and 20% of crude protein or 2850kcal ME/kg and 15% of crude protein, respectively. At 14, 21, 28, 35 and 42 days, the bones were weighed and the length and width of bones measured. The protein restriction reduced the body weight gain and the diameter of bone at second week of life. After 21 days of age no differences between treatments for these traits were observed. The body weight gain and femur growth were not affected by energy restriction. The high temperature (33°C) reduced weight gain and femur diameter from 21 to 42 days of age, and femur length at 42 days of age. The protein restriction at second week or the high environmental temperature after 21 st day of life decreased body weight gain and femur growth of broiler chickens.