Effects of physical and chemical treatments on quality of pistachio epicarp and lamb performance

Iran is the main pistachio producer in the world. There is about 298939 hectares of pistachio garden in Iran and annual dry pistachio production is 307036 tones. The production of pistachio by-product or the residue of pistachio after peeling is about 491257 tons annually. This by-product contains: %64.5 epicarp, %25 cluster, %10 leaf and %0.5 nut and shell. Pistachio epicarp contains high levels of tannins and other phenolic compounds. This by-product is deteriorated in less than 24 hours so it could not be stored for long term. This project was conducted to study the nutritive value of dried and ensiled pistachio by-product and assess its effect on performance of fattening lambs. First experiment was conducted to investigate the nutritive value of pistachio epicarp. Chemical analysis including CP, CF, EE, Ash, Ca, P, total phenolics, total tannins, condensed tannins were measured. Dry matter degradation on dried pistachio epicarp were measured and metabolizable energy was estimated using in vitro methods. Crude protein for dried and ensiled pistachio epicarp were 10.67 and 9.65 respectively. Metabolizable energy for dried and ensiled pistachio epicarp were 1.7 and 1.5 Mcal/KgDm respectively. Second experiment was conducted to assess the effect of pistachio epicarp on performance of fattening and carcass composition of lambs. Seven groups of ten male lambs (age 6 months and average weight 35.9±1.21 Kg), were fed for 90 days, iso-caloric, iso-nitrogenous diets, containing either no added pistachio epicarp (control) or added levels of 10, 15, 20, 25, 30 and 35 percentage pistachio epicarp in the rations (based on dry matter). After 90 days feeding, the lambs were slaughtered and dry matter intake, weight gain, body condition score, feed conversion and carcass composition parameters were measured. Maximum dry matter intake (2196.76 gr) and average daily gain (266.87 gr) and the best feed conversion ratio (8.23) observed in group 2 (contained 10 percents pistachio epicarp). The results showed that feeding lambs with pistachio epicarp up to 25 percentage of total dry matter intake did not affect lambs performance, feed conversion, body and health of animals. Third experiment was conducted to investigate the quality and nutritive value of ensiled pistachio epicarp with different levels of urea (0, 0.5, 1, and 1.5 percent) and molasses (0, 3 and 6 percent). A completely randomized design with 4×3 factorial arrangement was used to assess the effect of urea and molasses on silage quality. The content of dry matter, organic matter, crude protein, pH, flieg point, total volatile fatty acids and ammonia nitrogen, of the silages were measured. The optimum level of urea found in this study was 0.5%. Addition of higher levels of urea is not recommended due to increasing of pH and thereby decreasing silage quality. Addition of molasses positively affected silage quality and decreased pH.