Starving/re-feeding processes induce metabolic modifications in thick-lipped grey mullet (Chelon labrosus, Risso 1827)

Abstract

The effects of starvation and re-feeding on metabolites and tissue composition, GH/IGF-I axis, and digestive enzyme activities in juvenile thick-lipped grey mullet (Chelon labrosus) were evaluated. Fish were divided into three feeding groups (n=72, 82.00±4.09 g initial body mass). The control group was fed 1% of their body mass once a day throughout the experiment with commercial pellets. The other two groups were deprived of feed for 21 days (starved), or re-fed for 7 days after 14 days of food deprivation (re-fed). Full-length cDNAs from pituitary GH and hepatic IGF-I were cloned by screening a cDNA library or by PCR techniques. Furthermore, changes in their mRNA expressions were assessed by real time PCR in specimens maintained under the different feeding patterns. Results showed a negative growth in starved and re-feeding groups. Starvation induced a significant increase in plasma triglycerides as well as a decrease in liver glucose and glycogen. Re-feeding increased plasma glucose, lactate and protein, as well as liver glucose and glycogen. In addition, starvation significantly increased pituitary GH expression, while re-feeding down-regulated it. No significant changes were observed in hepatic IGF-I expression in any dietary treatment. Digestive enzyme activities were not significantly affected either by starvation or by re-feeding. The results of the present work suggest that juveniles of the thick-lipped grey mullet may easily adjust their metabolism under situations characterized by a short-term starvation and re-feeding.

Influence of stocking density on growth, metabolism and stress of thick- lipped grey mullet (Chelon labrosus) juveniles

“…Moreover, in other teleost species, a compensatory growth has been associated with a reduction of hepatic IGF-I mRNA levels (Picha et al, 2006), hence this fact observed at day 75 may have been due to increased plasma IGF-I levels as a consequence of its higher mRNA expression, maintaining similar SGR under the three different stocking densities studied. Furthermore, other chronic stress situations as starving produced the typical response of this axis with an increase in pituitary GH mRNA and a decrease in hepatic IGF-I mRNA in C. labrosus (Pujante et al, 2015), suggesting a clear dependence related to the stress source applied.…”

“…The main compounds of the somatotropic axis (i.e., GH and IGF-I) have been recently reported for C. labrosus by Pujante et al (2015). GH, secreted in the adenohypophysis and under hypothalamic control, is involved in the regulation of somatic growth through the induction of IGF-I (Björnsson, 1997;Chen et al, 1994;Pérez-Sánchez, 2000).…”

“…Primers for GH and IGF-I from C. labrosus (Table 1) were used as previously described by Pujante et al (2015) The melting curve was used to ensure that a single product was amplified and to check for the absence of primer-dimer artifacts. Results were normalized to β-actin (acc.…”

“…According to the previous work described by Pujante et al (2015), 50 ng and 500 ng of total RNA from the pituitary and liver, respectively, were used for reverse transcription in a final volume of 20 μL using the qSCRIPT™ cDNA Synthesis Kit (Quanta BioSciences). The qPCR was carried out with the Fluorescent Quantitative Detection System (Eppendorf Mastercycler ep realplex 2 S).…”

Genomic structure and molecular characterization of growth hormone and its expression response to different feed types in golden pompanoTrachinotus ovatus(Linnaeus, 1758)

“…It is well known that the neuroendocrine regulation of GH secretion in fish is multifactorial, with a balance of stimulatory and inhibitory neurohormones acting on pituitary somatotrophs. In addition, temperature (Picha et al, 2009;Zhou et al, 2015), season (Picha et al, 2009;Richmond, Jeanniard du Dot, Rosen, & Zinn, 2010), salinity (Moorman, Yamaguchi, Lerner, Grau, & Seale, 2016), starvation and refeeding (Pujante et al, 2015;Won & Borski, 2013), age (Li, Chen, Wong, & Lin, 2005;Richmond et al, 2010), gender (Ma et al, 2012), hormones (Linan-Cabello, Robles-Basto, & Mena-herrera, 2013;Wu, Li, Lin, & Li, 2012), diets (Li, Liu, Zhang, Ma, & Lin, 2013) and transgenosis (Abernathy et al, 2015;Leggatt et al, 2009;White, Volkoff, & Devlin, 2016) can also affect its distribution in tissues. Li et al (2013) found that cysteamine hydrochloride (CSH) feeding could induce the growth rate in Epinephelus coioides, and the luteinizing hormone-releasing hormone analogue (LHRH-A) could potentiate this growth stimulation effect.…”