A studdy on the effect of different protein levels in the diet on the nitrogen retention and excretion in growing pigs
2008
Ilchev, A., Thracian University, Stara Zagora (Bulgaria) | Ganchev, G., Thracian University, Stara Zagora (Bulgaria) | Pavlov, D., Thracian University, Stara Zagora (Bulgaria) | Valkova, P., Thracian University, Stara Zagora (Bulgaria) | Nikiforov, I., Thracian University, Stara Zagora (Bulgaria)
Balance experiments with 9 animals divided into 3 groups were conducted. Each experiment included a 5-day preliminary period and a 5-day analytical period during which the urine and faeces were collected. The animals were placed in special individual cages with a grid floor and double bed which allowed easy collection of urine and faeces. The animals were fed with 3 types of highly nutritive combined feeds. The control group was fed according to the requirements of “Danbred”, for the animals of the 2nd group the content of crude protein (CP) was increased with 15 above the norms, and for the 2nd group the protein content of the combined feed was decreased to 85% compared to the norms. As a result of the study it was found that the decreasing of the CP level with 15% during the starter period had a strong negative effect on the average daily gain and feed efficiency. Increasing the CP level with 15% above the recommended norms increased the average daily gain with 15.8% and improved the feed effectiveness with 6%. The high level of protein in the mixtures increased both the water intake and the amount of urine excreted. From 31.1% to 41.6% of the nitrogen consumed with the diet were excreted with the urine. During the starter period, from 15.7% to 18.9% of the nitrogen consumed with the feed was excreted with the faeces. With increasing the level of protein in the combined feeds the percent of the excreted nitrogen decreased.
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