Atlantic salmon (Salmo salar) is one of the worlds most domesticated fish. As production volumes increase, access to high quality and sustainable protein sources for formulated feeds of this ...carnivorous fish is required. Soybean meal (SBM) and soy-derived proteins are the dominant protein sources in commercial aquafeeds due to their low-cost, availability and favorable amino acid profile. However, for Atlantic salmon, the inclusion of soybean meal (SBM), and soy protein concentrate (SPC) in certain combinations can impact gut health, which has consequences for immunity and welfare, limiting the use of soy products in salmonid feeds. This study sought to address this challenge by evaluating two gut health-targeted enhancements of SBM for inclusion in freshwater phase salmon diets: enzyme pre-treatment (ETS), and addition of fructose oligosaccharide (USP). These were compared with untreated soybean meal (US) and fish meal (FM). This study took a multi-disciplinary approach, investigating the effect on growth performance, gut microbiome, and behaviors relevant to welfare in aquaculture. This study suggests that both enhancements of SBM provide benefits for growth performance compared with conventional SBM. Both SBM treatments altered fish gut microbiomes and in the case of ETS, increased the presence of the lactic acid bacteria Enterococcus. For the first time, the effects of marine protein sources and plant protein sources on the coping style of salmon were demonstrated. Fish fed SBM showed a tendency for more reactive behavior compared with those fed the FM-based control. All fish had a similar low response to elicited stress, although ETS-fed fish responded more actively than US-fed fish for a single swimming measure. Furthermore, SBM-fed fish displayed lower repeatability of behavior, which may indicate diminished welfare for intensively farmed fish. The implications of these findings for commercial salmonid aquaculture are discussed.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Arctic charr has emerged as a valuable candidate for diversifying commercial salmonid products for human consumption. The selective process is ongoing and the species has not been fully domesticated ...yet. Considering these factors, the impact of fish meal replacement on Arctic charr may differ from that observed in other farmed salmonids. The aim of this multidiciplinary study was to determine whether enhancements to SBM (enzyme pre-treatment and prebiotic addition) facilitate beneficial changes in the growth performance, gut microbiome, and behavior of Arctic charr. The results show that juvenile Arctic charr can tolerate relatively high inclusion levels (25 %) of soybean when supplemented with a prebiotic. However, enzyme pre-treatment of SBM had no beneficial effect on this species. The gut microbiota, mainly consisting of one dominant taxon, Mycoplasma sp., did not appear to be influenced by feed-related bacterial remnants or by the type of feed applied. Behavioral differences and similarities were observed in fish fed different diets. High consistency in the exploration trait was noted, with no impact of diet treatment on its mean value. A response to light stress on swimming activity occurred, regardless of diet treatment. Fish fed the untreated soybean diet exhibited greater boldness, while those fed the enzyme pre-treated diet showed high consistency in boldness. A negative correlation between boldness and growth performance was identified; however, no relationship was found between exploration and growth performance, nor was there a boldness-exploration syndrome in fish fed any of the diet treatments. These differences could not be attributed to variations in the gut microbiome, but other mechanisms that remain to be elucidated might be involved. Further research is needed on the impact of dietary proteins on the behavior and welfare of Arctic charr to optimize existing and new protein sources.
•Impact of enhancements to soybean meal is assessed on Arctic charr.•Traits such as growth, gut microbiome and behavior are examined.•High inclusion levels (25 %) of soybean, when supplemented with a prebiotic, could be successfully used.•Microbiota does not appear to be influenced by the diets.•Behavior consistency and mean value vary according to diets.
Disinfectants are essential for sanitary control. Nevertheless, their handling can be the cause of one-off accidents or chronic effects on human health if prevention and/or protection measures are ...not taken. The survey carried out in the ADAPT project among 108 companies (hatcheries, slaughterhouses, chicken and duck farms, fish farms) emphasises that a significant proportion of situations involves a high health risk, particularly for poultry and fish farmers. The implementation of prevention strategies should therefore be prioritised for the livestock sector, especially as awareness, information and training are less sustained there (smaller group of workers per company, more difficult to mobilise farmers on these subjects, etc.). The professionalization of farmers in terms of good practices for handling equipment (especially foam guns, which are most commonly used) and products (protection of the eyes, skin, respiratory tract, ventilation of the premises, etc.) must be reinforced in order to protect their health, the health of consumers and the environment, but also to guarantee the efficacy of disinfection. The use of alternatives or complementary methods making possible to use less disinfectant has been explored in the project: the use of barrier flora or enzymatic detergents seems to be a promising complementary method.
Les désinfectants sont indispensables à la maîtrise sanitaire. Néanmoins, leur manipulation peut être à l’origine d’accidents ponctuels ou d’effets chroniques sur la santé humaine si des mesures de prévention et/ou protection ne sont pas prises. L’enquête réalisée, conduite dans le projet aDAPt auprès de 108 entreprises (couvoirs, abattoirs, élevage de poulets et canards, piscicultures), souligne qu’une part nonnégligeable de situations sont à risque élevé pour la santé, en particulier pour les éleveurs avicole et pisciculteurs. La mise en place de stratégies de prévention est donc à prioriser pour le maillon élevage, d’autant plus que la sensibilisation, l’information et la formation y est moins soutenue (collectif de travail plus réduit par entreprise, mobilisation des éleveurs plus difficile sur ces sujets…). La professionnalisationdes éleveurs quant aux bonnes pratiques de manipulations du matériel (notamment canons à mousse, les plus utilisés) et des produits (protection des yeux, de la peau, des voies respiratoires, aération des locaux…) est à renforcer à la fois pour protéger leur santé, celle des consommateurs et celle de l’environnement, mais aussi garantir l’efficacité de la désinfection. L’utilisation d’alternatives ou méthodescomplémentaires permettant d’utiliser moins de désinfectant est aussi une piste qui a été explorée dans le projet : l’utilisation de flores de barrière ou détergents enzymatiques semble des méthodes complémentaires prometteuses.