Parâmetros reprodutivos de galos pesados alimentados com óleo residual da extração do azeite de oliva

Abstract

A residual oil from olive oil extraction industry was used instead of soybean oil in the diet of Cobb heavy roosters in order to evaluate bird’s reproductive parameters. Material was collected in February 2017 from an industry in Rio Grande do Sul interior and sent to Federal University of Pelotas to analyze chemical composition and to formulate the diets. A total of 40 roosters, from 25 to 39 weeks of age, were housed individually in boxes with 1,2m ². Two experimental diets were used; control diet, based on corn, soybean meal and soybean oil, and test diet (RO), where soybean oil was totally replaced by residual oil. In order to verify weight gain and feed intake, animals were individually weighed weekly in a digital scale with a maximum capacity of 15 kilograms. Food was supplied once a day, always at the same time. Seven semen collections were performed at every 15 days; in the first, birds were 27 and in the last, 39 weeks of age. Dorso-abdominal massage method was used; semen samples were collected in Falcon tubes with graduation of 0.1 mL, and sent to the laboratory for analysis of seminal volume, motility, concentration, and sperm morphology. Experimental design used was time-repeated measurements, where each animal represented one experimental unit and each treatment consisted of twenty replicates. No statistical difference (p>0.05) was observed between treatments at the different collection periods for the variables seminal volume, motility and sperm concentration. There was a statistically significant difference between treatments for body weight, where in periods 3 (p=0.0424) and 7 (p=0.0398), RO treatment presented higher weight gain than control treatment. Statistical differences (p=0.0120) were also observed between treatments for abnormal sperm morphology, where roosters fed residual oil presented lower sperm tail defects than control animals. Among collection periods, statistical difference was observed for motility (p=0.047) and sperm concentration (p=0.0188). Total replacement of soybean oil by residual oil from olive oil extraction in the diet of young Cobb heavy roosters does not affect volume, motility and sperm concentration; reduces defects in sperm tail, and promotes best weight gain control.