Effect of different dietary fats on hepatic gene expression in transition dairy goats

Eighteen second parity goats were selected for this study and divided in three homogenous groups of six animals each. Starting from week 2 before the expected kidding date to week 3 of lactation animals were fed the experimental diets: C, basal transition diet; PFISH, basal transition diet plus 47g/day of rumen protected fish oil as source of n-3 fatty acids; HPALM, basal transition diet plus 47g/day of hydrogenated palm oil (46.30% C16:0, 40.90% C18:0). Live body weight (LBW), body condition score (BCS), dry matter intake (DMI) and energy balance were assessed weekly. Milk yield and milk composition were recorded and analyzed on 4, 7, 15, and 21 days in milk (DIM). Alanine transaminase (ALAT), aspartate aminotrasferase (ASAT), non esterified fatty acids (NEFA), glucose, β-hydroxybutyrate (BHBA), and cholesterol plasma contents were measured weekly for all the experimental period. Liver mRNA levels for peroxisome proliferator-activated receptor-α (PPARA), acyl-coenzyme A dehydrogenase very long chain (ACADVL), acetyl coenzyme A carboxylase (ACACA), and carnitine palmitoyl-transferase 1A (CPT 1A) were determined 7 days (±1.43) before and 21 days after kidding by reverse transcription real time (RT) quantitative PCR (Q-PCR). Goats from the three experimental groups experienced negative energy balance after kidding with higher levels in both HPALM and PFISH than C (P ≤0.01) while no differences were detected among fat supplemented goats. Performance, milk composition, plasma metabolites and liver enzymes were similar in C, HPALM and PFISH, except for a significant effect of treatment on milk yield (P ≤0.01) in HPALM compared to C goats (3.65kg/day vs. 2.42kg/day, P =0.01) and ALAT content (P ≤0.01) in the first 21 DIM in HPALM than C and PFISH (14.25IU vs. 17.54IU and 16.80IU respectively; P ≤0.05). Treatment (P =0.08), day of treatment (P =0.06), and the interaction among treatment and day of treatment (P =0.08) showed tendencies to increased plasma NEFA content in HPALM during the post kidding period respect to PFISH and C. An interaction effect between treatment and day of treatment was found for PPARA (P =0.02), CPT1A (P =0.05), and ACADVL (P =0.05) mRNA levels. At 21 days in milk HPALM showed higher values in PPARA mRNA levels than C. mRNA levels of PPARA, CPT 1A, ACADVL, and ACACA showed trends to increase from 7 days before to 21 days after kidding in HPALM, contrary to PFISH. The present trial shows the effectiveness of hydrogenated palm oil, as an oil mainly containing C16:0 and C18:0, in enhancing mRNA expression of PPARA and selected target genes in liver of transition dairy goat.