Evaluation of different digestible lysine levels for male broilers during the period of 18 to 40 days of age

A total of 1.500 male Cobb 500 broilers were used to determine the optimal digestible lysine level for 18 to 40-day-old broilers. The experimental period started when broilers were 18 days old and had an initial average weight of 737 ± 20 g. A completely randomized experimental design was applied, with five lysine levels, totaling five treatments with 10 replicates of 30 birds each. The experimental diets contained equal energy and protein levels, and 0.86, 0.95, 1.04, 1.13, and 1.22% digestible lysine. The following parameters were evaluated: average body weight at 40 days of age, daily weight gain, daily feed intake, feed conversion ratio, carcass yield and parts yield, and abdominal fat percentage. There was a quadratic effect (p 0.05) of digestible lysine levels on average body weight at 40 days of age, daily weight gain, and breast yield, and a cubic effect on feed conversion ratio and abdominal fat. There was no influence of lysine levels of daily feed intake, carcass yield, leg, or wing yields. It was concluded that digestible lysine requirements for male broilers during the evaluated period was 1.22% for performance and 1.04% for carcass yield.

Evaluation of different digestible lysine levels for male broilers during the period of 18 to 40 days of age

A total of 1.500 male Cobb 500 broilers were used to determine the optimal digestible lysine level for 18 to 40-day-old broilers. The experimental period started when broilers were 18 days old and had an initial average weight of 737 ± 20 g. A completely randomized experimental design was applied, with five lysine levels, totaling five treatments with 10 replicates of 30 birds each. The experimental diets contained equal energy and protein levels, and 0.86, 0.95, 1.04, 1.13, and 1.22% digestible lysine. The following parameters were evaluated: average body weight at 40 days of age, daily weight gain, daily feed intake, feed conversion ratio, carcass yield and parts yield, and abdominal fat percentage. There was a quadratic effect (p 0.05) of digestible lysine levels on average body weight at 40 days of age, daily weight gain, and breast yield, and a cubic effect on feed conversion ratio and abdominal fat. There was no influence of lysine levels of daily feed intake, carcass yield, leg, or wing yields. It was concluded that digestible lysine requirements for male broilers during the evaluated period was 1.22% for performance and 1.04% for carcass yield.

Hatching distribution and embryo mortality of eggs laid by broiler breeders of different ages

This study investigated the hatching distribution of eggs from broiler breeders of different ages in distinct periods of incubation. Eggs were incubated in a single-stage experimental incubator. A number of 3.510 eggs were distributed into 3 treatments with 13 replicates of 90 eggs each. Treatments corresponded to breeder age: young (34 weeks), intermediate-age (44 weeks) and old (72 weeks) breeders. Eggs were transferred to the hatcher at 432 incubation hours, hatching was first checked at 449 hours, after which the number of hatched chicks was counted every 6 hours up to 515 incubation hours. After each count, hatched chicks were removed from the hatcher. Data were submitted to analysis of variance using measures repeated. A significant interaction between breeder age and incubation time was found. The total period required to hatch all incubated fertile eggs was not influenced by breeder age, which, however, affected hatching distribution. Eggs from old breeders hatched later as compared to young and intermediate-age breeders. More than 71% of the eggs had already hatched at 485 incubation hours, and 94% at 491 hours. Eggs laid by old breeders presented higher infertility and total embryo mortality, resulting in lower hatching percentage.

Ascorbic acid and citric flavonoids for broilers under heat stress: effects on performance and meat quality

The aim of this study was to evaluate the effects of increasing doses of ascorbic acid (AA) and citric flavonoids (quercetin and rutin) on the performance and meat quality characteristics of broilers submitted to cyclic heat stress. Four-hundred one-day-old female Ross 308 were housed in 40 battery cages a in temperature controlled room. Treatments consisted of 0, 250, 500, and 1000 g/ton on of AA + citric flavonoids. Birds were fed ad libitum until 32 day of age. Beginning on day 14 post-hatch until the end of the experiment, in order to simulate cyclic heat stress, the temperature inside the room was increased to 32°C for 5 hours, and decreased until reaching the comfort temperature corresponding to the age of the animals. Birds were slaughtered at 33 days of age, and carcass and commercial cuts yields were determined. Thighs and boneless breast samples were collected and frozen for subsequent analyses of pH, cooking loss, shear force, color, and Thiobarbituric Acid Reactive Substances (TBARS). Significant differences (p 0.05) were found for feed efficiency from 1 to 7 days of age, with the best values for the birds fed 0 and 250 g/ton on of AA + citric flavonoids. At the end of the experiment, there were no differences in other performance variables, carcass and parts yields, pH, shear force, color and TBARS. The meat of the birds supplemented with 250 g/ton on of product presented the lowest cooking loss.

Ascorbic acid and citric flavonoids for broilers under heat stress: effects on performance and meat quality

The aim of this study was to evaluate the effects of increasing doses of ascorbic acid (AA) and citric flavonoids (quercetin and rutin) on the performance and meat quality characteristics of broilers submitted to cyclic heat stress. Four-hundred one-day-old female Ross 308 were housed in 40 battery cages a in temperature controlled room. Treatments consisted of 0, 250, 500, and 1000 g/ton on of AA + citric flavonoids. Birds were fed ad libitum until 32 day of age. Beginning on day 14 post-hatch until the end of the experiment, in order to simulate cyclic heat stress, the temperature inside the room was increased to 32°C for 5 hours, and decreased until reaching the comfort temperature corresponding to the age of the animals. Birds were slaughtered at 33 days of age, and carcass and commercial cuts yields were determined. Thighs and boneless breast samples were collected and frozen for subsequent analyses of pH, cooking loss, shear force, color, and Thiobarbituric Acid Reactive Substances (TBARS). Significant differences (p 0.05) were found for feed efficiency from 1 to 7 days of age, with the best values for the birds fed 0 and 250 g/ton on of AA + citric flavonoids. At the end of the experiment, there were no differences in other performance variables, carcass and parts yields, pH, shear force, color and TBARS. The meat of the birds supplemented with 250 g/ton on of product presented the lowest cooking loss.

Hatching distribution and embryo mortality of eggs laid by broiler breeders of different ages

This study investigated the hatching distribution of eggs from broiler breeders of different ages in distinct periods of incubation. Eggs were incubated in a single-stage experimental incubator. A number of 3.510 eggs were distributed into 3 treatments with 13 replicates of 90 eggs each. Treatments corresponded to breeder age: young (34 weeks), intermediate-age (44 weeks) and old (72 weeks) breeders. Eggs were transferred to the hatcher at 432 incubation hours, hatching was first checked at 449 hours, after which the number of hatched chicks was counted every 6 hours up to 515 incubation hours. After each count, hatched chicks were removed from the hatcher. Data were submitted to analysis of variance using measures repeated. A significant interaction between breeder age and incubation time was found. The total period required to hatch all incubated fertile eggs was not influenced by breeder age, which, however, affected hatching distribution. Eggs from old breeders hatched later as compared to young and intermediate-age breeders. More than 71% of the eggs had already hatched at 485 incubation hours, and 94% at 491 hours. Eggs laid by old breeders presented higher infertility and total embryo mortality, resulting in lower hatching percentage.

Studies with sanguinarine like alkaloids as feed additive in broiler diets

This research included two studies evaluating the live performance of broilers fed Sangrovit® (minimum of 1.5% sanguinarine, a quaternary benzo[c]phenanthridine alkaloid extracted from Macleaya cordata). Both studies were conducted using Ross 308 female broiler chicks. Birds were fed corn-soybean meal all-vegetable diets without growth promoters with 5 treatments and 8 replications in each study. In the first study, treatments were composed of a Negative Control without feed additive and four diets with graded increases of Sangrovit of 12.5, 25, 37.5, and 50 ppm. In the second study, chicks received a similar diet from placement to 21 days of age and subsequently were given feeds with graded reductions in crude protein (CP) as follow: a Negative Control with 19.7% CP without sanguinarine, and then 19.7, 19.2, 18.8 and 18.3% CP supplemented with Sangrovit at 20 ppm. It was demonstrated that body weight was increased when birds were fed 50 ppm of Sangrovit at 21 d when compared to the Negative Control. Also comparatively to the Negative Control, cumulative feed conversion was improved for birds fed with Sangrovit at 37.5 ppm as well as feed intake from placement to 7 days at 12.5 ppm. No differences were observed in feed intake. Birds supplemented with Sangrovit and 18.8% CP had similar body weight gain and feed intake as the Negative Control with 19.7% CP. Mortality in both studies was not correlated with the treatments. Results from both studies indicate benefits of the supplementation of Sangrovit in diets for broilers.

Studies with sanguinarine like alkaloids as feed additive in broiler diets

This research included two studies evaluating the live performance of broilers fed Sangrovit® (minimum of 1.5% sanguinarine, a quaternary benzo[c]phenanthridine alkaloid extracted from Macleaya cordata). Both studies were conducted using Ross 308 female broiler chicks. Birds were fed corn-soybean meal all-vegetable diets without growth promoters with 5 treatments and 8 replications in each study. In the first study, treatments were composed of a Negative Control without feed additive and four diets with graded increases of Sangrovit of 12.5, 25, 37.5, and 50 ppm. In the second study, chicks received a similar diet from placement to 21 days of age and subsequently were given feeds with graded reductions in crude protein (CP) as follow: a Negative Control with 19.7% CP without sanguinarine, and then 19.7, 19.2, 18.8 and 18.3% CP supplemented with Sangrovit at 20 ppm. It was demonstrated that body weight was increased when birds were fed 50 ppm of Sangrovit at 21 d when compared to the Negative Control. Also comparatively to the Negative Control, cumulative feed conversion was improved for birds fed with Sangrovit at 37.5 ppm as well as feed intake from placement to 7 days at 12.5 ppm. No differences were observed in feed intake. Birds supplemented with Sangrovit and 18.8% CP had similar body weight gain and feed intake as the Negative Control with 19.7% CP. Mortality in both studies was not correlated with the treatments. Results from both studies indicate benefits of the supplementation of Sangrovit in diets for broilers.