Effects of bacterial treatment at early stages of Atlantic cod (Gadus morhuaL.) on larval survival and development

Abstract

Aims: To assess the effects of bacterial treatment at the earliest stages of cod rearing on the microbial load, larval development and performance, testing three bacterial strains (Carnobacterium divergens V41, Arthrobacter sp. and Enterococcus sp.) in vivo that were previously shown to have inhibitory potential towards fish pathogens in vitro. Methods and Results: A bacterial mixture was added eight times to the rearing water from the prehatch to the mid‐larval stage (a 38‐day period). Microbiological analysis of ova, larvae and rearing water was performed regularly. Larval performance and development were evaluated by survival rate, hypersalinity tolerance and physiological measurements. Different larval survival rates were observed within and between treatments, and possibly explained by variations in larval microflora and established probionts. Larvae from one silo, which had been bathed in the bacterial suspension, showed the highest survival rate (42·1%), lowest Vibrio levels, and were significantly heavier (19·3%) and more stress tolerant than control larvae (P < 0·01). This coincided with the intestinal establishment of two of the tested bacteria. Conclusions: Arthrobacter and Enterococcus strains added regularly to the rearing water from the postfertilized egg stage can become established in larval gastrointestinal tract. The Enterococcus strain was associated with increased larval growth, performance and microflora control, indicating its probiotic nature. Significance and Impact of the Study: Regular application of autochthonous probionts may promote larval welfare, development and stress tolerance at early stages, hence increasing production yield in intensive cod larviculture.

Microbiota of Atlantic cod (Gadus morhua L.) rearing systems at pre- and posthatch stages and the effect of different treatments

“…Bacterial bathing of ova (10 7 colony‐forming units (CFU) ml −1 rearing water for 30 min with intermitted flow) and larvae (10 6 CFU ml −1 for 2 h) was performed using bacterial suspensions prepared as described by Lauzon et al. (2010a).…”

“…We evaluated current hatchery practices (ova disinfection and antibiotic treatment of unhealthy larvae) and specific putative probiotics identified earlier (Lauzon et al. 2008) and applied to ova and larvae (Lauzon et al. 2010a) or rotifers.…”

Effects of synbiotic (Biomin IMBO) on haematological and immunological components of Russian sturgeon, Acipenser guldenstadti

“…Also, prebiotics are substrates that promote selectively the growth one or number of bacterial community in gut and hence help to loading of health-promoting microflora in gut, thus improving host welfare (Yazawa et al 1978;Gibson and Roberfroid title of synbiotics or synbiotic supplement can be more efficient than applying them alone (Chou et al 1991;Hagi and Hoshino 2009;Lauzon et al 2010;Montajami et al 2012;Nekoubin et al 2012). In fact, a synbiotic supplement is a mixture of probiotics and prebiotics (Fuller 1989;Vershuere et al 2000;Cerezuela et al 2011).…”

Probiotic Supplementation Promotes Calcification in Danio rerio Larvae: A Molecular Study

“…Lately, interest in the benefits of probiotic supplementation on teleost health [2], [3], immune function [4]–[8], stress tolerance [9] and development [10]–[13] has significantly augmented. Considerable attention has also been devoted to the effects of these bacteria on reproduction; indeed we found in a zebrafish model that the probiotic Lactobacillus rhamnosus affects the endocrine control of the hypothalamus–pituitary-gonadal axis by stimulating follicle maturation and inhibiting apoptotic processes naturally occurring in the ovary, thus enhancing fecundity [14]–[18].…”