Effect of stocking density on growth and serum concentrations of thyroid hormones and cortisol in Amur sturgeon, Acipenser schrenckii

Abstract

This study investigated the effects of different stocking densities on growth and serum concentrations of thyroid hormones and cortisol in Amur sturgeon, Acipenser schrenckii. Fish were reared at low, medium, and high stocking densities (initial experimental densities were 0.30, 0.75, and 1.78 kg m(-2), respectively) for 70 days. The results showed that high stocking density had negative effects on growth and feeding efficiency, and altered serum levels of thyroid hormones and cortisol in Amur sturgeon. A significant decrease in specific growth rate was observed as stocking density was increased. The feeding rate decreased significantly in the medium and high density groups, indicating that high stocking density reduced the food consumption of sturgeon. Food conversion ratio increased with increasing stocking density, suggesting that high stocking density might inhibit fish growth through decreasing food conversion efficiency. Serum concentrations of total triiodothyronine, free thyroxine, and free triiodothyronine were inversely related to stocking densities, whereas serum total thyroxine level of sturgeon stocked at different densities remained stable. Also, higher stocking density resulted in an elevation of serum cortisol level, indicating that the sturgeon stocked at the higher density experienced density-dependent physiological stress. These results suggest growth suppression caused by high stocking density might be related to both crowding stress and the declines in peripheral circulating levels of thyroid hormones, as well as associated with the reductions in both food consumption and food conversion efficiency.

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“…The present study highlighted the negative effect of high stocking density on growth and feed conversion capacity of labeo and catla as observed in previous studies (Ellis et al, 2002;Kebus et al, 1992;Lupatsch et al (2010); Li et al (2012). At this time fish exposed to a higher density showed significantly lower values in total length and weight as indicated by condition factor.…”

“…Stress in aquaculture is significantly important factor which impairs fish welfare by reduction in growth, abnormal behaviour and immuno-depression (Ellis et al, 2002;Lymbery, 2002;Papoutsoglou et al, 2006;Lupatsch, Santos, Schrana, & Verreth, 2010;Li, Liu & Xie, 2012). One of the major reasons causing chronic stress in farmed fish is stocking high density of fish in a given area to produce maximum commercial output (Iguchi, Ogawa, Nagae, & Ito, 2003;Hussein, 2012).…”

“…High stocking density has shown to affect some metabolic pathways, such as those related to lipids metabolism (Montero, Izquierdo, Robaina, & Vergara, 1999) and elevating the levels of cortisol Li et al (2012). Stress induced high levels of cortisol might remarkably reduce growth by altering activity of metabolic enzymes such as hepatic aminotransferase in channel catfish (Ictalurus punctatus) (Davis, Torrance, Parker, & Suttle, 1985), lipase and trypsin in Japanese flounder (Paralichthys olivaceus) (Bolasina, Tagawa, Yamashita, & Tanaka, 2006).…”

“…Elevated levels of cortisol due to density dependent stress have observed to interfere with thyroid function in in certain species such as Nile tilapia (Oreochromis niloticus) Walpita, Grommen, Darras, & Geyten, 2007). In Amur sturgeon (Acipenser schrenckii), serum concentrations of total triiodothyronine (T3), free T4, and free T3 have been found inversely related to higher stocking densities, whereas serum total T4 level remained stable Li et al (2012). Crowding stress-induced elevation in levels of cortisol while suppression in profile of T4 might be due to negative feedback mechanism of elevated cortisol level on hypothalamus-pituitary-interrenal axis thus decreasing (Walter et al, 2012).…”

PRODUKTIVITAS PASCALARVA IKAN SEMAH Tor douronensis (Valenciennes, 1842) PADA LINGKUNGAN EX SITU DENGAN PADAT TEBAR BERBEDA

“…Padat tebar merupakan faktor penting yang harus dipertimbangkan dalam budidaya ikan. Beberapa studi telah mengevaluasi pengaruh padat tebar terhadap pertumbuhan dan metabolisme pada spesies ikan budidaya, terutama ikan-ikan lokal (Kusmini et al, 2017;Rahman et al, 2016;Prakoso et al, 2016;Joko et al, 2013;Li et al, 2012;dan Herrera et al, 2009). Kegiatan budidaya membutuhkan optimalisasi padat tebar sepanjang siklus hidup dari spesies yang dipelihara untuk menghindari aktivasi sistem stres dan konsekuensi kerugian ekonomi (Jia et al, 2016;Barton, 2002).…”