Aim of this study was to evaluate the effects of diets enriched with polyunsaturated fatty acids (FA), using flax (F) and hemp seed (H) supplementation, on milk FA composition and mammary gland gene expression of lactating goats. A total of 18 Alpine goats were equally divided into three groups (F, H and control group C) depending on relationships among individuals, casein genotypes and production level. The chemical composition of the administered diets, in terms of neutral detergent fibre (NDF), starch, and ether extract (EE), were as follows, for C, L and H, respectively: 416, 422 and 433 g NDF/kg DM; 172, 132 and 132 g starch/kg DM; 26, 63 and 56 g EE/kg DM. The experiment focused on two time points during lactation: T0, when all the goats were fed the same diet (about 45 days in milk, DIM); T1, when the animals were fed the three different diets (about 150 DIM). At these two time points, a total of 150 mL of milk was collected for both milk fatty acid composition analysis and RNA extraction from milk somatic cells. The FA composition was determined by gas chromatography. The concentration of milk fat at T1 increased of almost one percentage point between the animals subjected to the supplemented diet with F and H respect to the control group. The treatment with flax and hemp seed caused a clear and significant decrease in the concentration of all the saturated fatty acids, in par6cular short and medium chain fatty acids, with a more pronounced effect on milk of goats supplemented with flax seed. Massive, parallel, high\throughput, RNA\seq was used to generate the caprine milk transcriptome. In total, we obtained from 14.951.867 to 34.867.432 uniquely mapped reads that covered 88.93% of the current annotated transcripts, which represented 12.436 mRNA transcripts, across all the samples. Among the three dietary treatment groups, no differentially expressed genes (p < 0.05, false discovery rate q < 0.05) were found for the control group at the two time points, whereas 133 and 491 genes resulted differentially expressed in T1 with respect to T0 in the F and H groups respectively. This study investigated the complexity of the response of goat mammary gland to different diets. Further integrated analysis of differential gene expression and genome analysis will permit the identification of candidate key genes for enhancing milk FA composition in goat.
Transcriptional profiling of mammary gland and milk fatty acid composition in response to diets supplemented with flax and hemp seed in dairy goats
S Chessa;P Cremonesi;E Capra;B Lazzari;G Battelli;F Turri;B Castiglioni
2015
Abstract
Aim of this study was to evaluate the effects of diets enriched with polyunsaturated fatty acids (FA), using flax (F) and hemp seed (H) supplementation, on milk FA composition and mammary gland gene expression of lactating goats. A total of 18 Alpine goats were equally divided into three groups (F, H and control group C) depending on relationships among individuals, casein genotypes and production level. The chemical composition of the administered diets, in terms of neutral detergent fibre (NDF), starch, and ether extract (EE), were as follows, for C, L and H, respectively: 416, 422 and 433 g NDF/kg DM; 172, 132 and 132 g starch/kg DM; 26, 63 and 56 g EE/kg DM. The experiment focused on two time points during lactation: T0, when all the goats were fed the same diet (about 45 days in milk, DIM); T1, when the animals were fed the three different diets (about 150 DIM). At these two time points, a total of 150 mL of milk was collected for both milk fatty acid composition analysis and RNA extraction from milk somatic cells. The FA composition was determined by gas chromatography. The concentration of milk fat at T1 increased of almost one percentage point between the animals subjected to the supplemented diet with F and H respect to the control group. The treatment with flax and hemp seed caused a clear and significant decrease in the concentration of all the saturated fatty acids, in par6cular short and medium chain fatty acids, with a more pronounced effect on milk of goats supplemented with flax seed. Massive, parallel, high\throughput, RNA\seq was used to generate the caprine milk transcriptome. In total, we obtained from 14.951.867 to 34.867.432 uniquely mapped reads that covered 88.93% of the current annotated transcripts, which represented 12.436 mRNA transcripts, across all the samples. Among the three dietary treatment groups, no differentially expressed genes (p < 0.05, false discovery rate q < 0.05) were found for the control group at the two time points, whereas 133 and 491 genes resulted differentially expressed in T1 with respect to T0 in the F and H groups respectively. This study investigated the complexity of the response of goat mammary gland to different diets. Further integrated analysis of differential gene expression and genome analysis will permit the identification of candidate key genes for enhancing milk FA composition in goat.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
