Effects of electron irradiation, sodium hydroxide and poly ethylene glycol on the utilization of pistachio by-products by Zandi male lambs

• Electron irradiation and NaOH decreased tannin of pistachio by-products.
• NaOH increased and irradiation decreased cell wall of pistachio by-product.
• Irradiation increased and NaOH decreased rumen degradability of pistachio by-product.
• Irradiation increased utilization of pistachio by-product by lambs.

The current study evaluated the effects of treating pistachio by-products (PBP) with electron irradiation (ER; 30 kGy), sodium hydroxide (NaOH; 4%) or polyethylene glycol (PEG) on nutrient digestion, growth performance and blood metabolites of Zandi lambs. Twenty male Zandi lambs (21 ± 1.52 kg BW) were randomly assigned to a control diet (containing 22% untreated PBP), ER-PBP (containing 22% electron irradiated PBP), NaOH-PBP (containing 22% NaOH treated PBP) or PEG-PBP (containing 22% PEG treated PBP) for 70 d. Data were analyzed using the GLM procedure of SAS for a completely randomized design and significance level was set at 0.05. Treating PBP with ER decreased (−5.21%) neutral detergent fiber (NDF), whereas treating with NaOH increased (+32.24%) NDF content compared to control PBP. The concentrations of phenolic compounds were lower in NaOH-PBP than in control PBP or ER-PBP. Potential degradability (a + b) and effective ruminal disappearance of dry and organic matters were lower in NaOH-PBP compared to control or irradiated PBP. Feeding ER-PBP improved feed intake, weight gain and average daily gain compared to other experimental diets (P < 0.05). Feeding ER-PBP, PEG-PBP or NaOH-PBP similarly increased (P < 0.01) dry matter and crude protein digestibility compared to control group. Among different serum metabolites only total protein was affected by experimental diets, which was increased (P < 0.01) in lambs fed PEG-PBP compared to other experimental diets. Alanine aminotransferase (ALT) was decreased (P < 0.01) in the lambs received dietary treatments compared to those received control diet.