Supplementation with dietary linseed oil during peri-puberty stimulates steroidogenesis and testis development in rams.

Omega-3 polyunsaturated fatty acids (ω-3 PUFAs), such as α-linolenic acid (ALA), eicosapentaenoic acid, and docosahexaenoic acid, are involved in male reproductive function. In this study, we investigated the effects of linseed oil (LO) as a source of ALA on the steroidogenesis and changes of testicular histology in rams. Sixteen 3-month old rams during peri-puberty were randomly assigned into two groups. Eight rams were assigned as the control group, and the other received LO (4% dry matter of total diet) as the LO treatment group. After an 81-day feeding trial, the rams were slaughtered and investigated. Results revealed that compared with control group, diet containing LO did not affect body weight (36.87 ± 0.53 kg vs. 37.65 ± 0.64 kg, respectively; P = 0.361), average daily gain (227.47 ± 5.82 g vs. 237.95 ± 9.22 g, respectively; P = 0.353) and epididymis weight (40.77 ± 4.41 g vs. 45.53 ± 4.01 g, respectively; P = 0.398), however, it up-regulated PUFAs metabolism and steroidogenesis-related genes mRNA expression (P < 0.05), and increased plasma estradiol concentration (14.88 ± 0.67 pg/mL vs. 19.50 ± 1.27 pg/mL, respectively; P < 0.05). Therefore, LO stimulated seminiferous tubule development and increased the number of Sertoli cells (19.17 ± 2.14 vs. 27.2 ± 2.39, respectively; P < 0.01), germ-cell layers, as well as testis weight (148.65 ± 22.66 g vs. 249.96 ± 30.63 g, respectively; P < 0.05). All these results suggested that LO can improve testis development during peri-puberty by regulating steroidogenesis in rams' testes.