Dietary l-arginine supplementation improves semen quality and libido of boars under high ambient temperature

Abstract

l-Arginine is a nutritionally essential amino acid for spermatogenesis and plays versatile roles in animal health and can be utilized as a potential agent to improve reproductive performance of boars under high ambient temperature. The present study aimed to determine whether dietary l-arginine could alleviate heat stress-induced infertility in boars. In all, 20 boars (PIC 1040; 248.59±3.84 kg BW and 407.65±6.40 days of age) were selected and randomly assigned to four groups (group 0.0%, basal diet; group 0.6%, 0.8% or 1.0%, basal diet added with 0.6%, 0.8% or 1.0% l-arginine (wt:wt), respectively.) The four diets were made isonitrogenous by addition of appropriate amounts of l-alanine. Boars were pre-fed the corresponding experimental diet for 42 days. Then, the semen characteristics and libido were accessed for 6 weeks during the hot summer period (25.5° to 33.0°C). Results show that dietary l-arginine remarkably improved sperm motility, normality, total sperm number and effective total sperm number. Also, dietary l-arginine improved semen antioxidant capacity, such as decrease of malondialdehyde and 8-Hydroxy-2'-deoxyguanosine content in sperm (P<0.05), increase of the ratio of glutathione and oxidized glutathione, total antioxidant capacity, glutathione peroxidase and catalase activities in seminal plasma (P<0.05). Most of mitochondria contained intact ultrastructure in l-arginine-supplemented group which also accompany with higher ATP content than the 0.0% group. The boars fed 0.8% l-arginine show increased levels of estradiol-17β and testosterone and exhibit improved libido performance than boars in the 0.0% group. Adding dietary l-arginine linearly increased (P=0.002) nitric oxide content (as l-arginine increased). The scrotal surface temperature in the 0.6%, 0.8% and 1.0% group were decreased by 0.9°C, 0.9°C and 0.4°C, respectively, compared with the 0.0% group. l-Arginine levels caused linear effect on semen quality and antioxidant capacity, also caused quadratic effect on libido performance. During the hot summer months, the predicted optimal l-arginine levels for best semen quality and antioxidant capacity was 0.8% to 1.0% and for best libido performance was 0.8%. It can be concluded that l-arginine can be used as an effective agent to alleviate heat stress-induced infertility of boar, and that 0.8% to 1.0% can be considered as the optimum dosage.

A RNA-Seq Analysis to Describe the Boar Sperm Transcriptome and Its Seasonal Changes

“…In a recent study, Argenti et al (2018) identified increased superoxide dismutase anti-oxidant activity in the sperm of boars raised in sub-tropical Brazil in the summer months probably as a molecular attempt to reduce the presence of ROS and sperm damage (Argenti et al, 2018). Moreover, dietary strategies based on supplementary Zinc (Li et al, 2017) and l-arginine (Chen et al, 2018) have been related to a reduction of oxidative stress and improvement on the epididymal function and boar sperm quality in summer.…”

Heat stress, a serious threat to reproductive function in animals and humans

“…Specific treatments and managerial interventions could help to mitigate or counteract the effects of HS on semen quality. For example, in pigs, dietary supplementation with an essential amino acid such as l ‐arginine could alleviate summer HS (33°C) that resulted in infertility by (a) improving total sperm number and motility; (b) improving semen antioxidant capacity, assessed by a decrease in sperm malondialdehyde and 8‐hydroxy‐2′‐deoxyguanosine content as well as by an increase in the ratio of glutathione to oxidized glutathione, total antioxidant capacity, glutathione peroxidase, and CAT activities in seminal plasma; (c) improving sperm ATP content; (d) preserving mitochondrial ultrastructure; (e) increasing levels of estradiol‐17β and testosterone; (f) improving libido performance (Chen et al, ).…”

Addition of L-arginine in skim milk extender maintains goat spermatozoa quality in chilled temperature for five days

“…Intact, the plasma membrane (IPM) has a negative correlation to MDA and is positively correlated with the viability and motility of spermatozoa. The low dose of L-arginine results in higher viability and motility of spermatozoa; mediated, it increases the antioxidant capacity of semen, which results in a decrease in MDA [29].…”