Dietary supplementation with 15% tomato pomace (Solanum lycopersicum L.) improves sperm production and antioxidant status in aged male broiler breeders

Abstract

The objective was to investigate effects of dietary tomato pomace (TP) and L-Arginine (L-Arg; 10% above nutritional recommendation) in aged male broiler breeders. Thirty male broiler breeders (Ross 308), 58 wk old, were randomly and equally allocated into five experimental groups: basal diet (C); 5% TP-supplemented (T-5); 10% TP-supplemented (T-10); 15% TP-supplemented (T-15); and L-Arg supplemented (L-10) groups. In contrast to the Control and TP-supplemented groups, sperm of L-10 roosters had higher C14:1, C16:0 and C18:1 n-9c proportions, total saturated fatty acid (FA) contents, and n-6:n-3 ratios, but a lower C22:4 n-6 content (P<0.05). However, sperm of T-15 roosters had increased C18:2 n-6, C22:6 n-3 and total unsaturated FA contents but reduced n-6:n-3 ratios compared to Control birds (P<0.05). Additionally, serum of T-15 roosters had lower cholesterol and triglyceride (TG) concentrations, along with decreased aspartate aminotransferase (AST) activity (P<0.05). In serum of T-15 and L-10 roosters, there were increases (P<0.05) in total antioxidant capacity (TAC) and uric acid (UA) and a reduction (P<0.05) in malondialdehyde (MDA) concentration. The T-15 roosters had higher (P<0.05) serum testosterone concentration and testes glutathione peroxidase (GPx) activity. Superoxide dismutase (SOD) content was reduced (P<0.05) in L-10 roosters. Seminiferous tubule diameter (STD) and seminiferous epithelium thickness (SET) were increased in all groups fed TP (P<0.05) and T-10 and T-15 roosters had increases (P<0.05) in tubular differentiation indices (TDI). The T-15 and L-10 groups had higher mRNA expressions of AKT1 and Nrf2 (P<0.05). In conclusion, in aged male broiler breeders, up to 15% TP supplementation is recommended to improve reproductive performance by enhancing testes histology and antioxidant status.

Keywords: Arginine; Gene expression; Male broiler breeder; Testosterone; Tomato pomace.

Fig 1

Light micrograph of the seminiferous tubules’ cross-section captured on a scale of 150 μm using a ×40 magnification of a light microscope (Olympus, BH2, Japan) equipped with a SONY on-board camera (Zeiss, Cyber-Shot, Japan). Arrows “a” and “b” indicate examples of sections that were considered to measure SET and STD, respectively, in testes tissue samples (samples were obtained at Week 12 of the experiment) for histological study.

Fig 2

Light micrographs of the seminiferous tubules’ cross-sections (samples were obtained at Week 12 of the experiment) were captured on a scale of 200 and 50 μm using a ×40 objective lens on a light microscope (Olympus, BH2, Japan) equipped with a SONY on-board camera (Zeiss, Cyber-Shot, Japan).

Fig 3

Effects of various dietary tomato pomace and L-Arg supplementation on serum testosterone concentrations (samples were obtained at Week 10 of the experiment) of aged male broiler breeders. Roosters (58 wk of age; n=6 per treatment) were fed a basal diet (C), or a basal diet supplemented with 5, 10 or 15% tomato (T-5, T-10 and T-15 respectively), or a diet supplemented with L-Arg 10% above the nutritional recommendation (L-10). Values represent mean ± SEM of blood samples collected from six birds per treatment. ^a,bMeans without a common superscript differed (P<0.05).

Fig 4

Relative mRNA expression of the AKT1 gene. The data represent relative mRNA expression of AKT1 in testicular tissue of aged male broiler breeders (samples were obtained at Week 12 of the experiment). Roosters (58 wk of age; n=6 per treatment) were fed a basal diet (C), or a basal diet supplemented with 5, 10 or 15% tomato (T-5, T-10 and T-15 respectively), or a diet supplemented with L-Arg 10% above the nutritional recommendation (L-10). Following the Kolmogorov-Smirnov normalize test and 2-ΔΔCt calculations, the mean values (for each treatment) were reported as fold change, and the treats with fold change > 2 or <0.5 considered significantly different compared to the control group.

Fig 5

Relative mRNA expression of the Nrf2 gene. Data represent relative mRNA expression of Nrf2 in testicular tissue of aged male broiler breeders (samples were obtained at Week 12 of the experiment). Roosters (58 wk of age; n=6 per treatment) were fed a basal diet (C), or a basal diet supplemented with 5, 10 or 15% tomato (T-5, T-10 and T-15 respectively), or a diet supplemented with L-Arg 10% above the nutritional recommendation (L-10). Following the Kolmogorov-Smirnov normalize test and 2^-ΔΔCt calculations, mean values (for each treatment) were reported as fold change, and treatments with fold change > 2 or <0.5 were considered significantly different compared to the control group.