Glomerulonephritis and immunosuppression associated with dietary essential fatty acid deficiency in gilthead sea bream, Sparus aurata L., juveniles

Abstract

An experiment was conducted to determine the effect of an essential fatty acid (EFA) deficient diet on growth, immune status and renal morphology of juvenile gilthead sea bream, using two diets: a control diet containing 2% (DW) of n-3 high unsaturated fatty acid (n-3 HUFA) and a diet formulated to be deficient in EFA for this species and containing 0.5% DW of n-3 HUFA (diet NFA). After 9 weeks of feeding the EFA-deficient diet fish showed a reduction in growth compared with the control group (107.48 ± 9.14 and 123.14 ± 11.87 g final weight respectively). Fish fed the NFA diet showed a reduction in the erythrocyte volume together with increased erythrocyte fragility, haemoglobin content and red blood cell count in comparison with fish fed the control diet. EFA deficiency also reduced cellular immunity in terms of neutrophil activity and the number of circulating lymphocytes. The serum alternative complement pathway was markedly reduced in fish fed the EFA deficient diet. Fish fed the control diet showed glomeruli with a well-defined Bowman's space and normal renal tubes. However, up to 88% of fish fed the EFA-deficient diet showed alterations in renal morphology affecting at least 50% of the glomeruli, which showed extreme dilation of capillaries and occlusion of Bowsman's capsule. Mesangial proliferation and diffuse thickening of the capillary walls, as well as renal tube degeneration, were also observed.

Dietary n−3 LC-PUFA requirements in silvery-black porgy juveniles (Sparidentex hasta)

“…However, in the current study except for Hb content variation between different groups, the other hematological parameters were not changed. The divergence between the present study and the above-mentioned of Montero et al (2004) might be due to the fact that n−3 LC-PUFA deficiency in silvery-black porgy did not result in anemia, as it occurred in gilthead sea bream. Lee et al (2001) also reported that dietary n−3 deficiency did not affect RBC counts, Hb and Hct parameters in rockfish (Sebastes schlegeli), which is in line with the results of current study.…”

“…In the present study, fish fed diet with 0.1% n−3 LC-PUFA showed some signs of n − 3 LC-PUFA deficiency such as decreased growth and feed utilization, a reduction in feed intake, increased HSI and alteration in the fatty acid profile of the liver. These results were similar to those already reported in other carnivorous species like gilthead seabream (Montero et al, 2004), European sea bass (Dicentrarchus labrax) (Skalli and Robin, 2004) and large yellow croaker (Larmichthys crocea) (Zuo et al, 2012). Essential fatty acid requirements of a fish species are generally correlated with dietary lipid levels, fish developmental stage and culture conditions (Glencross, 2009;NRC, 2011).…”

“…Thus, lower levels of dietary n− 3 LC-PUFAs in silvery-black porgy resulted in an increase in n− 9 fatty acids, mainly oleic acid. This symptomatology has also been reported in fish fed EFA deficient diets (Montero et al, 2001(Montero et al, , 2004 and in carnivorous fish species fed with vegetable oils (Caballero et al, 2002;Menoyo et al, 2004;Piedecausa et al, 2007). Liver damages can be induced by malnutrition which leads to disorders in lipid metabolism, as a consequence of malfunction in the production of bile salts, lipoproteins and fat absorption (Lall, 2010).…”

“…In this sense, Montero et al (2004) reported that EFA deficiency in gilthead seabream juveniles led to an increase in the hemoglobin concentration, MCH and RBC counts. However, in the current study except for Hb content variation between different groups, the other hematological parameters were not changed.…”

Lipids in Marine Ecosystems

“…Further up the food web, EPA and DHA are important in stress resistance [30] and immunity [31] in finfish, and dietary DHA is also needed for finfish schooling behaviour [32] and growth in shellfish [29]. DHA from the marine food web is also thought to have played a critical role in human evolution [33].…”