P. Shakeri, A. Riasi, M. Alikhani , H. Fazaeli and G. R. Ghorbani

Journal of Animal Physiology and Animal Nutrition DOI: 10.1111/jpn.12005, In press)

Abstract

The study investigated physiological effects of pistachio by-product silage (PBPS) substituted in Holstein male calves diets and its effects on the growth performance. Twenty four Holstein male calves (4- 5 months of age and 155.6± 13.5 kg BW) were randomly assigned to one of four experimental diets (n= 6); contained 0, 6, 12, and 18% of PBPS (DM basis) respectively. During a six months experiment, dry matter intake and weight gain were recorded and blood and urine samples were collected at different times. Results showed that mean dry matter intake was not affected by different levels of PBPS in diets. But the calves with 6% PBPS had the highest average daily gain (P< 0.05) and the lowest feed conversion ratio (P< 0.05). The calves fed 12 and 18% PBPS had lower albumin, white blood cell, hemoglobin and packed cell volume (P< 0.05) than those fed other diets. However, other serum metabolites, complete blood count (CBC), insulin and liver enzymes were not affected by the experimental diets. The long period feeding of PBPS at different levels had no significant effect (P> 0.05) on pH, specific gravity, the number of white and red blood cells and epithelial cells count in urine. The animals did not show any symptom of illness or toxicity during the experimental period and all of the blood and urine parameters were in a normal range. It was concluded that substitution of PBPS up to 18% of the total diet that provide up to 18.2 g kg^-1 DM total tannin had no adverse effects for Holstein male calves.

Keywords: Pistachio, phenolic compounds, silage, metabolites, urine