Welfare improvement using alginic acid in rainbow trout (Oncorhynchus mykiss) juveniles

Abstract

The present study explored alternative strategies to improve the health status and growth metabolism in cultured juvenile fish. In this context the effects of alginic acid administration on the welfare of rainbow trout juveniles were investigated. Both the hepatic gene expression of heat shock protein 70 and the cortisol plasma levels were evaluated in order to estimate the possible beneficial role of alginic acid in improving animal well-being. At the same time the body weight was measured and was correlated with the hepatic expression of insulin-like growth factor I, myostatin, and two isoforms of the thyroid receptor. Finally, improvement of the immune system was investigated by monitoring the expression of innate immune-related genes, such as interleukin1β, interleukin8 and toll-like receptor3, in the spleen. The data obtained demonstrated an improvement in the welfare of rainbow trout juveniles, revealed by growth and innate immune response enhancement by alginic acid administration. These results may be of great importance for the further development of more sustainable aquaculture practices, and can be considered as a biotechnological application to produce a safer product for human health.

Dietary Ergosan as a Supplemental Nutrient on Growth Performance, and Stress in Zebrafish (Danio Rerio)

“…In this study, all treatment groups presented higher growth indices (BWG, SGR, and CF) and lower FCR than the control group after a period of 90 days feeding. These findings are in agreement with the on rainbow trout that received fermented S. cerevisiae (Barnes et al 2006) and Ergosan (Gioacchini et al 2010). In this study, Ergosan enhanced growth indices and feed intake.…”

“…In this study, Ergosan enhanced growth indices and feed intake. These results are in agreement with those achieved with the administration of alginic acid in rainbow trout (Gioacchini et al 2010) and Beluga sturgeon Huso huso (Jalali et al 2009). Conversely, alginic acid had no effects on tilapia (Oreochromis niloticus) (Merrifield et al 2011) and sea bass (Dicentrarchus labrax) (Bagni et al 2005).…”

Effect of dietary alginic acid on juvenile tilapia (Oreochromis niloticus) intestinal microbial balance, intestinal histology and growth performance

“…40-60 g; although not significant, heavier mortalities were (Faghani et al 2008). Future studies are required to determine the cause of this observation in tilapia but Ergosan studies in rainbow trout are indicative that dietary Ergosan may affect the expression HSP genes and cortisol levels that could positively affect stress responses (Gioacchini et al 2008(Gioacchini et al , 2010. Due to the aggressive behaviour observed in the present study and the subsequent mortalities, growth performance and feed utilisation parameters should be viewed with a level of caution.…”

“…However, the lack of effect on growth performance by dietary Ergosan in the present study is in keeping with several other studies in fish (Raida et al 2003;Bagni et al 2005;Faghani et al 2008). Contrary to these findings, dietary Ergosan has been reported to improve growth performance of Beluga sturgeon Huso huso (Jalali et al 2009), shrimp Litopenaeus vannamei (Montero-Rocha et al 2006) and rainbow trout (Gioacchini et al 2010). In the present study, elevated carcass protein, approaching significance (P=0.12), was observed in the Ergosan -ed tilapia; similarly, elevated carcass protein has also been reported in sturgeon fed dietary Ergosan (Jalali et al 2009).…”

“…Several studies have demonstrated the efficacy of alginates to increase the non-specific defense responses of fish (Fujiki et al 1994;Fujiki and Yano 1997). Dietary applications of the commercial product Ergosan (Schering-Plough Aquaculture, UK), which contains 1% alginic acid extracted from Laminaria digitata, have also been observed to improve the innate immune system of fish (Miles et al 2001;Peddie et al 2002;Bagni et al 2005;Gioacchini et al 2008Gioacchini et al , 2010. Most alginic acid studies in fish have assessed the systemic immune response or the adjuvant effect.…”