DIETARY YEAST HYDROLYSATE IMPROVES GROWTH PERFORMANCE, ANTIOXIDANT CAPACITY, IMMUNITY, AND INTESTINAL MICROBIOTA OF JUVENILE GIANT FRESHWATER PRAWN

The present study aims to investigate the influence of dietary yeast hydrolysate on growth performance, antioxidant capacity, immunity, and intestinal flora of juvenile giant freshwater prawn (Macrobrachium rosenbergii). Five experimental diets were formulated by incorporating 0%, 0.5%, 1%, 2% and 4% of yeast hydrolysate into the basal diet hereafter referred to as YH0, YH0.5, YH1, YH2 and YH4, respectively. The diets were administered to 50 juvenile M. rosenbergii with an initial weight of 0.0451 ± 0.003 g in triplicates for eight weeks. The amount of dietary yeast hydrolysate required for optimum growth performance, antioxidant capacity and immunity in M. rosenbergii ranged from 0.9% to 2.6%. Collectively, these findings suggest that, moderate dietary yeast hydrolysate supplementation exerts improves growth performance, antioxidant capacity, and immunity in M. rosenbergii. Furthermore, dietary yeast hydrolysate modulates intestinal microbiota composition.

Introduction

Intensive aquaculture has gained widespread adoption due to its automated operations, elevated productivity, and cost-efficiency. However, this practice often results in densely populated cultured aquatic species and excessive feeding, increasing the chances of aquatic animal exposure to stress factors. The stress resulting from intensive aquaculture include accumulation of excrement and ammonia nitrogen (Jia et al., 2023), oxygen deprivation-induced stress to aquatic organisms (Zheng et al., 2021) and antibiotics misuse (Chen et al., 2020). The aforementioned issues impede growth performance, degrade muscle quality, and suppress the immune response of aquatic organisms, ultimately exerting destructive effects on the overall profitability of aquaculture (Lin et al., 2018, Ding et al., 2020). Therefore, finding ways to alleviate stresses, thus improve growth performance and immunity response of aquatic animals is the basis for realizing sustainable development of aquatic products. Feed additives exhibit favorable regulatory effects to alleviate stress among the available methods (Vijayaram et al., 2022).

Yeast has emerged as one of the promising feed additive candidates (Fu et al., 2021, Shurson, 2018). Yeast hydrolysate derived from the enzymatic degradation of yeast cells, has high protein content and abundant nucleotides, β-glucan, mannan, small peptides, and free amino acids (Park et al., 2013, Fu et al., 2021, Jin et al., 2018, Yin et al., 2022). Accordingly, the effects of yeast hydrolysate on feed efficiency, growth and immune response have been investigated in several aquatic organisms (Andriamialinirina et al., 2020, Rahimnejad et al., 2023). Supplementing yeast hydrolysate into the diet has been shown to promote growth performance, immunity, and resistance to ammonia stress in Pacific white shrimp (Litopenaeus vannamei) (Jin et al., 2018) and enhance digestive capacity in yellow catfish (Pelteobagrus vachelli ♂ × P. fulvidraco ♀) (Fu et al., 2023) and Pacific white shrimp (Yang et al., 2020a, Yang et al., 2020b). Furthermore, yeast hydrolysate has been found to increase antioxidant capacity in the serum, the expression of immune-related genes in the liver, and enhance disease resistance in largemouth bass (Micropterus salmoides) (Gong et al., 2019). The results from these studies suggest that, yeast hydrolysate is beneficial for enhancing growth performance, feed efficiency and immunity response in cultured species.

Feed additives have been intimately linked to the intestinal microbiota, which plays a crucial role in growth performance and wellbeing of aquatic animals (Shi et al., 2022). A previous study indicated that dietary supplementation with brewer’s yeast hydrolysate mitigated the presence of pathogens and altered gut bacterial community in largemouth bass (Zhou et al., 2018). Furthermore, commercial probiotics derived from Saccharomyces cerevisiae and S. elipsoedas increased aerobic bacterial count and lactic acid bacteria population in rainbow trout (Oncorhynchus mykiss) intestine (Adel et al., 2017). However, the beneficial effects of yeast hydrolysate in other cultured species are currently not well established, an aspect requiring studies to investigate.

The giant freshwater prawn (Macrobrachium rosenbergii), known for its large size, has become a prominent prawn species in freshwater aquaculture across various nations, attributable to its wide dietary range, fast growth, and promising economic prospects (Ganesan et al., 2022). However, the application of intensive farming practices, as well as the discharge of industrial and agricultural pollutants, have induced environmental stresses in giant freshwater prawn culture. The stresses exert inhibitory effects on growth performance, immune response and embryonic development, increase disease outbreak rates, escalate medication use, and reduce production efficiency of giant freshwater prawn (Ganesan et al., 2022, Kumaresan et al., 2017, Hooper et al., 2023). Enhancing aquaculture efficiency and achieving environmentally friendly and healthy farming practices for giant freshwater prawn have been the focus of researchers worldwide. It has been reported that feed additives including Clostridium butyricum (Sun et al., 2022), probiotics (Azad et al., 2019) and betaine (Dong et al., 2020) exhibited positive effects on growth performance and immunity of M. rosenbergii. The effects of live brewer’s yeast (Saccharomyces cerevisiae) cells on growth performance of M. rosenbergii post-larvae has been studied based on the nutritional quality (Prasad et al., 2013). However, studies exploring the effects of yeast hydrolysate on growth performance, antioxidant capacity, immunity and microbiota in M. rosenbergii are currently not available. The lack of such studies limits the application of yeast hydrolysate for enhancing growth performance, antioxidant capacity and immunity response for sustainable M. rosenbergii aquaculture.

Therefore, the current study explored the effects of yeast hydrolysate on growth performance, hepatopancreatic antioxidant capacity, serum biochemical parameters, and intestinal flora of M. rosenbergii. The findings obtained provide a scientific basis for the application of yeast hydrolysate in prawn feed aquaculture.

Experimental diets and proximate analysis

The basal diet was formulated by using fish meal and soybean meal as protein sources, fish oil and soybean oil as lipid sources, and corn starch as the carbohydrate source. Five experimental diets were produced by incorporating yeast hydrolysate into the basal diet at levels of 0%, 0.5%, 1%, 2%, and 4% and hereafter referred to as YH0, YH0.5, YH1, YH2 and YH4, respectively. The formulation and composition of the experimental diets is presented in Table 1. The feed preparation process involved

Growth performance and survival

Feeding the experimental diets initially increased and then decreased WG and SGR of the prawns with increasing dietary yeast hydrolysate concentration (Fig. 1). The prawns fed on the YH1 diet had significantly higher WG (Fig. 1A) and SGR (Fig. 1B) than those fed on the YH0, YH2 and YH4 diets (P < 0.05). Nonetheless, there was no significant differences in WG and SGR between YH1 and YH0.5 diets (P > 0.05). Moreover, the prawns fed on the YH0.5 and YH2 diets, on one hand, and those fed on YH0, YH2

Discussion

The present study revealed significant effects of dietary yeast hydrolysate on the growth performance of M. rosenbergii. Incorporating 0.5 to 1% yeast hydrolysate in the diet resulted in maximum prawn WG. Similar positive effects of moderate dietary yeast hydrolysate supplementation on growth performance have been reported in various species such as oriental river prawn (M. nipponense) (Xiong et al., 2021), Pacific white shrimp (Jin et al., 2018), Nile tilapia (Oreochromis niloticus)

Conclusion

The findings of this study demonstrate that appropriate dietary yeast hydrolysate supplementation exerts beneficial effects on the growth performance, antioxidant capacity, and immune response in giant freshwater prawn. Moreover, dietary yeast hydrolysate modulates the diversity and composition of intestinal microbiota. We recommend supplementing 0.9% to 2.6% yeast hydrolysate in the diet of giant freshwater prawn to promote their growth performance and overall health. Future studies on yeast.

Source : Youqin Kong, Qiuyu Gao, Dong Zhou, Qiao Feng, Zhili Ding, Samwel Mchele Limbu, Jinyun Ye. Dietary yeast hydrolysate improves growth performance, antioxidant capacity, immunity, and intestinal microbiota of juvenile giant freshwater prawn (Macrobrachium rosenbergii), Animal Feed Science and Technology, Volume 319, 2025, 116196. https://doi.org/10.1016/j.anifeedsci.2024.116196.