Investigating the Effect of Replacing Soybean Meal with Poultry Slaughterhouse Waste Mixed with Rice Bran and Urea on Performance, Blood and Rumen Parameters of Fattening Lambs

Protein quality is important for feedlot lambs; protein imbalance may reduce growth rate, increase feeding costs, and emission of gases, particularly methane. In low-producing ruminants, protein requirements can be satisfied mainly with microbial protein, which is produced from nitrogen sources and high fiber. On the other hand, in high-producing ruminants, like feedlot lambs, their high protein requirements for maximum growth rate are not completely satisfied by the microbial protein produced in the rumen. Considering this, it is necessary to provide protein sources that escape rumen degradation. Traditionally, sources of dietary protein are seen as either being of animal or vegetable origin.. In this study, the effect of replacing soybean meal with poultry slaughterhouse waste enriched with  rice bran and urea on performance, rumen and blood parameters of fattening lambs were investigated.

In this experiment, male Kurdish lambs (16 heads with an average weight of 32 ± 2.7 kg and age of 4 to 6 months) were used. At the beginning of the experiment, the lambs were vaccinated and fed antiphrastic drugs. The experimental feed, which included 50 percent of poultry slaughterhouse waste, 47.5 percent rice bran and 2.5 percent urea was substituted for soybean meal at the levels of 33, 66 and 100% and was used in the feeding of fattening lambs. The experiment was carried out as a completely randomized design with four treatments including 1- control diet, 2- 33% mixed feed, 3- 66% mixed feed and 4- 100 mixed feed instead of soybean. The habitation of the lambs to the experimental diet was carried out for 14 days before the start of the fattening period.  The lambs consumed diets containing experimental feed for 84-days   The results of the experiment were analyzed with the  GLM procedure of the SAS statistical program.

The amount of dry matter intake, daily weight gain and feed conversion ratio were not affected by the experimental  treatments. The highest incease in blood glucose concentration was related to lambs receiving the diet containing the highest level of experimental diet (p<0.05). The amount of ammonia nitrogen in the rumen fluid decreased with increasing  of experimental feed level (p<0.05).  The amount of volatile fatty acids in the rumen was  significantly different between experimental treatments (p<0.05). The highest amount of digestibility and crude protein was related to the control group (p<0.05). The diet containing 100 percent of the experimental feed had the highest digestibility for NDF.

In general, the results of this study showed that complete replacement of  soybean meal with experimental feed containing 50% of poultry slaughterhouse waste, 47.5% of rice bran and 2.5% of urea in the diet is possible without any negative effect on fattening performance.