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The Impact of Two Different Cold-Extruded Feeds and Feeding Regimens on Zebrafish Survival

Zebrafish (Danio rerio) is one of the top model organisms used in biomedical research. Therefore, it is fundamental that zebrafish facilities continuously improve husbandry methods to provide fish with the best physiological and welfare conditions that suit each experimental purpose. Nutrition is a husbandry aspect that needs further optimization, as it greatly affects growth, reproduction, health and behaviour. Here, we have compared the impact of different feeding regimens on zebrafish survival, growth and reproductive performance. Mutant and wild-type zebrafish were raised using several combinations of two cold-extruded processed feeds—Skretting GemmaMicro and Sparos Zebrafeed—and one live feed (rotifers). Zebrafeed outperformed GemmaMicro in terms of survival rate, and embryo viability was also higher when the spawners were fed with Zebrafeed either from larval stage or upon sexual maturation. In contrast, GemmaMicro favoured growth, both in size and weight. The use of rotifers until 60 days post-fertilization improved survival of fish co-fed with GemmaMicro, while delaying their growth. Zebrafeed® performance was not affected by co-feeding rotifers. Overall, we showed that different nutritional formulas affect physiological parameters, allowing for the establishment of feeding protocols adapted to the objectives of each facility. At the same time, we validated Skretting®GemmaMicro and Sparos®Zebrafeed as two commercially available feeds that are well suited for zebrafish nutrition in a laboratory environment.Get more news about Micro Precision Cold Extrusion Part Exporter,you can vist our website!

Research in different models has historically promoted the importance of nutrition in outcomes related to development, health, disease and responses to toxic compounds in food and the environment [1,2,3]. Yet, there is a striking absence of literature showing the role of nutrition as an important regulator of health and disease in zebrafish. If nutrition is to be accepted as a critical part of health management, it is imperative to consider the typical end goal of fish production in a research setting: to provide fish that are clinically healthy and representative of animals exhibiting normal physiology [4]. Although the known nutritional requirements of other cyprinid fish can be an acceptable approach to zebrafish requirements [5,6], this does not take into account some particularities of the species, such as high growth rate, infinite growth, continuous egg production after maturation. The feeds and feeding regimens implemented by research laboratories for rearing zebrafish are varied [7]. In some cases, feeds and feeding regimens are implemented without a formal evaluation [8]. While the world aquaculture relies on fish meal (FM) as the main protein source in aquafeeds [9], research over the last decade has resulted in a significant decrease in the portion of FM in fish feeds, and there are species-specific limits in the FM replacement rate by, for example, soybean (SBM), above which irreversible damages occur affecting fish growth performance and welfare [10,11]. Therefore, meeting the specific nutritional requirements of zebrafish will potentiate growth and promote an optimal physiological status, minimizing undesirable effects and allowing for more consistent results [12]. The use of purified diets with defined ingredients facilitates the determination of the precise nutritional requirements, promoting optimal performance in fish stocks [13].

Having alternative suppliers of live and processed feeds, which results in fish with high, optimized and standardized growth, survival and breeding rates, is a management requisite for zebrafish facilities. Comparing different feeds tested in previous studies [14,24] that have demonstrated good impacts on growth and reproductive performance is the first step towards achieving this. This study aimed to understand which combination of commercial processed feeds, Skretting®GemmaMicro® and/or Sparos®Zebrafeed®, complemented with Type “L” saltwater live rotifers Brachionus plicatilis, is more suitable for improved survival, growth and reproductive performance.

In this study, we used two strains of zebrafish that are widely used in biomedical research: wild-type AB and non-pigmented Nacre mutant (mitfa −/−). Embryos were obtained by overnight crossing 8–10 females with 4–6 males of each strain stock in 1.7 L sloping breeding tanks (Tecniplast®). The housing and husbandry of all animals were performed as published [25], and dietary adaptations were in accordance with the specifications of the present study (Table 1). Briefly, all embryos were collected, placed in 90 mm diameter petri dishes with standard embryo medium [26] and kept at 28 °C in an incubator with a photoperiod of 14 h:10 h/light:dark up to 5 days post-fertilization (dpf). Early 6 dpf larvae were transferred to 3.5 L tanks at a density of 35 fish/tank, each containing 400 mL of fish water and 100 mL of type “L” saltwater rotifers (Brachionus plicatilis) solution (0.5 mL of RG Complete™, ~800–900 rotifers/mL, conductivity ~3 ppt). At 8 dpf, water flow was started through the 3.5 L tanks, and larvae began to be fed according to their experimental group (Table 1).