Tannins ability to modify the fatty acid composition of milk and meat has received great attention recently. The aim of this study was to evaluate the effects of feeding pistachio hull (PH, source of tannin) and polyethylene glycol (PEG) supplementation on milk yield, compositions and fatty acid profile particularly vaccenic and rumenic acid in Sannen dairy goats. Nine Sannen dairy goats (average DIM, 71.5 ± 6.5 d and milk production, 1.5 ± 0.25 kg) were used in a 3×3 latin square design. Three treatments were formulated: T1) Control, without PH, T2) 30% PH (DM basis) that provided 18.1 g condense tannin per kg DM of diet and T3) 30% PH + 1% PEG (DM basis). In T2 and T3, PH was replaced with alfalfa hay. Milk yield was recorded daily. Milk samples were taken at the 3 last days of sampling. Milk fatty acids were analyzed on a Gas Chromatography with a flame-ionization detector and column. Statistical analysis was performed using the MIXED procedure of SAS 9.1. The results of this study showed that milk yield and compositions (except for protein) were not affected by addition of PH and PEG. Percentage of C18:1, trans-9, C18:1, cis-9 and C18:1, trans-11 (vaccenic acid), and C18:2, cis-9, trans-11 CLA (rumenic acid) significantly increased with addition of PH in T2. Concentration of UFA, MUFA, and PUFA in treatments including of tannin (with PH) were significantly higher than control (without PH). Concentration of short-chain FA (SCFA) in T2 and T3 was significantly lower than the control. Using of tanniniferous sources had no negative effects on milk production and compositions of dairy goats. The addition of PH could increase the level of poly unsaturated fatty acids content of goat milk and PEG supplementation will conserve it while blocking PH’s tannin content.

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