Balanço e eficiência de utilização de compostos nitrogenados em pequenos ruminantes alimentados com resíduo da indústria de doces/sucos em substituição ao milho

Abstract

Goats and sheep breeding are extremely important activities for Brazil’s Northeastern region, because it is where most of these animal are. Being important not only for maintaining the rural population, but also being their main source of income. The nitrogen balance is the difference between the amount of nitrogen ingested and excreted via feces and urine. The evaluation of the nitrogen utilization is an important information to base the discussion about nutritional requirements for maintenance and production. The experimental design was a double latin square 4 x 4, each one composed by one species. The experiment lasted for 88 days (four periods of 22 days each), being each of them composed by 14 days of adaption to the diet and eight days of data collect. For this experiment there were used four male goats and four male sheep, all of them were castrated and had a rumen fistula. Their average initial weight was 70,1 kg ± 0,51 e 63,5 kg ± 1,08, for sheep and goats, respectively. The animals were fed twice a day in form of complete ration at 8 a.m. and 4 p.m., adjusted daily in function of the animal’s intake with a margin of 10 and 15% of leftovers. The samples of diets and leftovers were pre-dried in a forced ventilation oven at a temperature of 55 ± 5 ºC, for 72 hours; subsequently, they were ground in a 1 mm sieve strainer, for analysis regarding the dry matter and nitrogen contents. Variables were evaluated using analysis of variance and regression using the SAS PROC MIXED. All diets had a positive nitrogen balance, which indicates that the replacement of corn by RID did not significantly influence nitrogen digestion and the diets met the N requirements. It is noted that there was a significant difference (P < 0.05) in N intake and the amount of N in feces between species, being higher in sheep. The concentration of N-Ureic in blood plasma was influenced (P < 0.05) by the treatment, with a decreasing linear effect with the replacement of corn by the mixture of RID + FGM.