Effects of starvation and refeeding cycles on spermatogenesis and sex steroids in the Nile tilapia Oreochromis niloticus

Changes in fatty acids, blood biochemistry and mRNA expressions of genes involved in polyunsaturated fatty acid metabolism in brown trout (Salmo trutta) during starvation and refeeding

“…Fishes are exposed to short‐ or long‐term starvation during their life because of biotic and abiotic factors, such as migration, reproduction and seasonal water temperature changes (Miller et al., 2009; Rahmati et al., 2019; Yang et al., 2019). Fishes can cope with starvation via biochemical and physiological adaptations (Dar et al., 2018), such as managing energy expenditure (McCue, 2010), regulating cortisol metabolism (Sales et al., 2020), activating the antioxidant defence system (Furne et al., 2009) and changing the gene expressions involved in different metabolic pathways (Salem et al., 2007). Farmed fish are also subjected to starvation to decrease the negative effects of stress and to improve water and product quality (Einen et al., 1998; Morshedi et al., 2017).…”

Transcriptomic analysis of mechanism underlying the effect of induced molting on semen quality and reproductive performance in aged Houdan roosters

“…Starvation causes severe adverse effects on sperm density and sperm motility in breeder roosters, consistent with studies showing negative effects on spermatogenesis after starvation in mammals ( Grizard, 1997 ; Yu et al, 2016 ). The cause of the decrease in sperm density and sperm motility may be related to increased apoptosis and decreased cell proliferation ( Sales et al, 2020 ). After refeeding for 15 d, no sperm were collected, likely due to fasting induced DNA breakdown in primary spermatids and delayed progression through the meiotic stages of spermatogenesis ( de Alvarenga and de Franca, 2009 ; Liu et al, 2013 ; Penaranda et al, 2016 ).…”

“…After refeeding, the diameter of the seminiferous tubules became significantly larger until R32, when spermatozoa in the central region of the seminiferous tubule reappeared. It follows that refeeding delays spermatogenesis but does not cause testicular damage ( Saleset al, 2020 ).…”

“…SFKs are expressed in almost all mammalian cells, they are nonreceptor protein kinases that phosphorylate a variety of cellular proteins on tyrosine, leading to the activation of protein targets in response to environmental stimuli ( Xiao et al, 2019 ). We speculate that long-term food restriction leads to nutritional deficiency, fat generation is inhibited, and fat decomposition is accelerated ( Yuet al, 2016 ; Saleset al, 2020 ), resulting in lipid (blood lipid) deficiency. The decrease of blood lipid level is mainly due to the increase of cholesterol consumption during food restriction.…”

Catch‐up fat in male adults induces low testosterone and consequently promotes metabolic abnormalities and cognitive impairment

“…30 That refeeding after the caloric restriction is able to elevate the testosterone level mildly to some extent but not recover completely and promptly, 31 might be an important reason for the inappropriate normal LH levels and reduced testosterone levels in male CUFA humans and rats in the present study. 32,33 Additionally, neuronal insulin receptor knockout mice become insulin resistant and also have a reduction in LH concentrations and low testosterone concentrations, 34 implying that the IR of the central system during refeeding after caloric restriction might also be a contribution to hypogonadotropism in male CUFA rats.…”