Rafael de Barros

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 posthatch 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.

Reassessing flavophospholipol effects on broiler performance

The objective of this study was to evaluate bird responses to flavophospholipol at higher doses than those recommended by the Brazilian legislation. A trial was conducted with 900 male broilers divided into five doses of flavophospholipol: 0, 2, 4, 8 and 16 mg/kg. The performance evaluation was conducted weekly until 42 days of age. The evaluated parameters were: weight gain, feed conversion corrected for mortality, feed intake and mortality. At the end of experimental period, birds supplemented with growth promoter differed from the negative control for weight gain and feed conversion in the period from 1 to 42 days. Body weight gain and feed conversion were significantly higher for birds fed 16 mg/kg of flavophospholipol, compared with treatment without the growth promoter in the period from 1 to 21 days. In the accumulated period from 22 to 42 days, all doses were different for the negative control for feed conversion and body weight gain. The performance improvement was maximized at the dosage of 10.1 mg/kg for feed conversion ratio and 10.9 mg/kg for body weight gain by regression analysis. Flavomycin can be used as a growth promoter to improve feed conversion ratio and body weight gain in broilers from 1 to 42 days of age.