Abstract
Aquaculture is one of the most important methods of food production in the world, and shrimp farming plays an important role in this field. Unfortunately, increasing shrimp production in the current way brings problems such as the spread of diseases and adverse environmental effects. The use of probiotics in shrimp nutrition helps a lot in increasing safety and protecting the environment. In this study, in order to investigate the effects of using the commercial probiotic PowerPro Chitica on the performance and survival of shrimp, an experimental design was designed in which three levels of 100, 150 and 200 mg/kg of probiotic were present compared to the control group. The temperature of the culture water was 28-33 ° C and the salinity of the water was 35-42 ppm. The results of the study showed that the use of different levels of probiotics had significant effects on final weight, final length, feed conversion ratio, specific growth rate and survival rate. The use of different levels of probiotics significantly reduced feed conversion ratio, increased final weight, increased final length, increased relative weight rate and increased specific growth rate compared to the control group. In general, the use of probiotics in shrimp nutrition could have positive effects on performance parameters and survival rate, which in turn can greatly help farmers in increasing profitability.
Introduction
Aquaculture is one of the important methods in producing human food needs in the world. It plays a very important role in human health. Shrimp is one of these aquatic animals that has been well received. However, unfortunately, shrimp farming in current methods causes many problems for the environment (1). The use of antibiotics in the past decades was widely used in aquatic animal nutrition to control diseases and as a growth stimulant. Later, researchers realized the negative effects of antibiotics on human health and also the disruption of the natural intestinal microflora ecosystem in animals, which led the European Union to take an important step in eliminating antibiotics in animal nutrition in 2006 (2). After eliminating growth-promoting antibiotics, researchers sought to find a suitable alternative that would have positive effects. Among the tested alternatives were acidifiers, probiotics, prebiotics, synbiotics, phytobiotics, etc. Probiotics were one of the options that showed the best performance in their use (3, 4). Probiotics are living organisms that exert beneficial effects on the health of the host animal by modulating the body’s microbial flora. Researchers introduced probiotics as a suitable alternative to antibiotics because they both strengthen the immune system and are environmentally friendly. Among the most important probiotic genera used in shrimp nutrition that can help the health of water and animals are Pseudomonas and Bacillus. The mechanism by which probiotics prevent the negative effects of pathogens on animals is unknown, but it may be due to the inhibition of pathogen adhesion to the digestive tract and the production of substances that inhibit the growth of pathogens (5,9). A 2019 study examined the effect of probiotics on shrimp larvae. The results of this experiment showed that the use of probiotics improved water quality, improved survival rates, and the production of digestive enzymes (3). This study was conducted to investigate the effects of using the probiotic PowerPro Chitica on the performance and survival of Western Whiteleg Shrimp.
Materials and Methods
The probiotic used in this product was obtained from Chitika Company under the brand name Chitika PowerPro, which according to the company’s claim contained eight effective bacterial strains (Lactobacillus rhamnosus, Bacillus subtilis, Bacillus lichiniformis, Enterococcus faecium, Pediococcicus acidi lacticus, Lactobacillus casei, Lactobacillus acidophilus and Lactobacillus plantarum). The amount of probiotic used in this experiment was added to the shrimp feed in powder form.
The Western white-leg shrimp (L. Vannamei) used in this study were obtained and reared from the Pasifid Shrimp Breeding Center in Goiter, Chabahar. After being transferred to the breeding center, the shrimp were transferred into fiberglass tanks with a volume of 100 liters. The average initial weight of the shrimp was 53±3 mg, and they were fed three times a day. The cultured shrimp were divided into two groups: control and probiotic, and 4 replicates were considered for each experimental treatment. The tanks were filled with seawater that had been passed through fine filters. The salinity of the water was 35-42 ppm and its temperature was on average 28-33 ° C. The dissolved oxygen content in the water was 5-7 mg / liter, and the light and dark periods were set as 12 hours of light and 12 hours of darkness. The amount of feed added to the tanks for feeding was considered 7% of body weight, and this was so that this feed was consumed, and if less was consumed, less was given to them, and the amount of feed was controlled daily. Losses were counted and weighed daily, and at the end of the 60-day period, the survival rate of the shrimp was evaluated. At the end of the period, the shrimp were starved for 24 hours and then weighed.
The percentage of body weight gain in the entire culture period was also obtained from the following formula.
100*(initial weight/(initial weight-final weight))=Relative weight rate
The specific growth rate was also obtained from the following equation, which expresses the daily weight gain in terms of percentage of body weight.
Day/(natural logarithm of initial weight-natural logarithm of final weight (grams))=Specific growth rate
Statistical analysis:
The experimental treatments in this experiment included 1- control treatment 2- 100 mg/kg probiotic 3- 150 mg/kg probiotic 4- 200 mg/kg probiotic, each with 4 replications. All obtained data were entered into Excel software and sorted. Then, normality was tested using JAMP software and then statistical analysis was performed using SAS-9.3 software using GLM procedure in a completely randomized design. Duncan’s multiple range test was used to compare the means at a significance level of 0.05.
Results and discussion
Table 1 reports the effect of different levels of commercial probiotic Power Pro Chitica on growth performance and survival rate. The experimental treatments had significant effects on the evaluated parameters. The final weight of shrimp in the groups receiving probiotics was significantly higher than the control group. In a study conducted by Ajdari et al. in 2023, they investigated the effect of using different strains of probiotics on shrimp. They reported that using probiotics in shrimp feeding improved the final weight compared to the control group. The final length of shrimp in the control group was significantly less than that of groups receiving probiotics (3). Many studies have been conducted to investigate the effect of probiotics on the final length of shrimp, and reports indicate an increase in final length with probiotic consumption (2,8). The growth rate and relative weight rate in shrimp receiving Power Prochitica probiotic were significantly higher than in the control group. The feed conversion ratio was significantly reduced in the groups receiving 150 and 200 mg/kg of probiotics compared to the control group. The survival rate in groups fed with treatments containing probiotics was significantly higher than in the control group. The life of shrimp is very closely related to microorganisms. Beneficial probiotic bacteria are a vital tool for improving growth performance, acting as a source of nutrients, vitamins, and digestive activators (enzymes that positively affect feed intake) (1,6). Probiotics enhance feed efficiency in shrimp by stimulating digestive enzymes and maintaining a balance of gut microbes, improving nutrient absorption and utilization, and ultimately increasing shrimp survival and growth performance (4). Studies on diets containing probiotics have shown that probiotics affect the improvement of gut microflora and the production of extracellular enzymes, thereby improving feed efficiency and growth performance in shrimp (4,7).
| Table 1. Effect of different levels of commercial probiotic PowerPro Chitica on growth performance and survival rate of Western white shrimp (for 60 days) | ||||||
| Treatment* | ||||||
| 1 | 2 | 3 | 4 | SEM | P Value | |
| Final weight | 8.27b | 10.62a | 10.91a | 10.97a | 0.4658 | 0.0040 |
| Final length | 50.00b | 53.58a | 53.94a | 54.04a | 0.5724 | 0.0008 |
| Relative weight rate | 1701b | 1984a | 2052a | 2148a | 48.74 | 0.0002 |
| Specific growth rate | 4.30c | 4.50bc | 4.65ab | 4.74a | 0.0491 | 0.0003 |
| Food conversion ratio | 3.21a | 3.28ab | 2.77b | 2.74b | 0.0890 | 0.0085 |
| Survival rate | 79.92b | 85.75a | 88.78a | 89.78a | 1.1400 | 0.0002 |
| a-c Means with different letters in a column are significantly different at the five percent level.
*Experimental treatments in this experiment include 1- Control treatment 2- 100 mg/kg probiotic 3- 150 mg/kg probiotic 4- 200 mg/kg probiotic |
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Conclusion
The use of probiotics in aquaculture has increased significantly in recent years. In the present study, the use of different levels of probiotics in the diet of Western whiteleg shrimp had positive effects on performance and survival. In general, the use of 100 and 150 mg/kg probiotics in shrimp diet improved weight gain, increased length, reduced feed conversion ratio, and increased final weight compared to the control group.
