Effects of processed recycled poultry bedding with tannins extracted from pomegranate peel on the nutrient digestibility and growth performance of lambs
The aim of this experiment was to decrease the rumen degradability rate of recycled poultry bedding (RPB) protein using pomegranate peel extract (PPE) as the tannin source. Furthermore, to study the effects of this processing method on nutrient digestibility, rumen and blood parameters, nitrogen retention, growth performance, carcass characteristics of male Arabi lambs, and the economic value of diets and production. Thirty-two Arabi lambs (19.7 ± 2.45 kg bodyweight, 90 ± 12 days old) were randomly assigned to one of four dietary treatments including a control and RPB treated with 20%, 25% and 30% PPE on a dry matter basis. Compared with the control, treatment of RPB with PPE did not affect apparent digestibility of dry matter, organic matter, neutral detergent fibre or acid detergent fibre. However, apparent crude protein digestibility decreased significantly. Dietary treatments had no effect on ruminal pH, although ammonia-nitrogen and blood urea nitrogen concentration decreased in diets containing RPB treated with PPE. All lambs were in a positive nitrogen balance and the highest nitrogen retention was observed in the dietary group that was fed RPB treated with 25% PPE. Adding PPE to RPB up to 25% significantly increased final bodyweight, total gain, average daily gain and warm carcass weight, and improved the economic values of production as it decreased the price of each kilogram diet and cost per unit of production (each kilogram bodyweight). The dry matter intake and gain efficiency were unaffected by treatments. Therefore, treatment of RPB with 25% PPE in the finishing diets of Arabi lambs improved growth performance and nitrogen metabolism without affecting feed intake and gain efficiency, and warm carcass weight, and improved the economic values of production.
Keywords: ammonia nitrogen, blood urea nitrogen, carcass characteristics, economic analysis, nitrogen balance