High stocking density induces crowding stress and affects amino acid metabolism in Senegalese sole Solea senegalensis (Kaup 1858) juveniles

Abstract

Fish held at high stocking densities are generally exposed to chronic stress situations that impose severe energy demands and may predispose the ¢sh to infection. Senegalese sole Solea senegalensis (Kaup) juveniles (78.8 AE 18.9 g body weight) were maintained at low (LSD; 4 kg m À 2 at the end of the experiment), medium (MSD; 9 kg m À 2 ) and high (HSD;14 kg m À 2 ) stocking densities during a period of 63 days. Although disease outbreaks were observed in ¢sh reared at HSD, growth and food consumption did not vary among di¡erent treatments. Results from plasma cortisol and free amino acids (FAAs) showed signi¢cant di¡erences among di¡erent rearing densities pointing to HSD as stressful rearing condition. However, higher plasma glucose and osmolality levels indicated that ¢sh held at MSD may also be under stress. The higher usage of FAAs from the HSD group may be due to the higher demand for energy production in order to cope with stressful rearing conditions, higher rate of protein synthesis or due to synthesis of other important metabolites related to stress response. Therefore, results from the present study point out to HSD as a stressful rearing condition and suggest that crowding stress may a¡ect amino acid requirements.

Survival and growth responses of snakehead fish Channa striata Bloch. juvenile in aerated and unaerated acid sulfate water

“…Due to stress, the fish needs a lot of energy to adapt against stress condition caused by environmental changes. The high energy requirement for survival will stimulate the mobilization of glucose into the blood (Costas et al, 2008;Abdel-Tawwab, 2012). The rearing medium of the snakehead fish juvenile without aeration created a conducive condition for the snakehead fish (stagnant water without agitation), with optimum environmental conditions, the osmoregulation process became minimum and consequently the survival of the snakehead fish would be high.…”

Influence of stocking density and type of feed on the rearing of crucian carp, Carassius carassius (L.), larvae under controlled conditions

“…It could be suggested that fish which are much more advanced ontogenetically are able to react more intensively to stimuli around them. This may have directly affected physiological factors resulting from stress (Costas et al 2008) and consequently reduced growth rate. Thus, the lack of differences in crucian carp larvae growth in high stocking densities (above 200 ind.…”

Eye Color Pattern During Isolation Indicates Stress-Coping Style in Nile Tilapia Oreochromis niloticus L.

“…Fish exposed to stress will undergo a series of biochemical and physiological changes in an attempt to adapt to the stressful condition (Costas et al, 2008). Environmental stressors affect hematological conditions in fish, which in turn, are reflected in physiological functions (Ipinmoroti, 2015).…”