New Mix For Fish
Proteolytic enzymes (Phytase)
Phytases have been employed in animal feeds for several years, used primarily for reducing the environmental impact and phosphorus loads of farm effluents. The beneficial effect of dietary phytase has been associated with the limited ability of monogastric animals to utilize dietary plant phytates. To date, numerous studies have shown the positive effect of phytase supplementation on the availability of dietary phosphorus and trace minerals within plant-based feeds for monogastric farm animals, including farmed fish and shrimp. Individual feed ingredients may also be improved with phytases as an exogenous treatment, also termed pre-conditioning dephytinization prior to mixing. This review presents data on the potential benefit of phytase application for fish and shrimp species in improving digestibility of phosphorus and other minerals as well as organics nutrient fractions such as protein, amino acids, and lipids.
Effect of phytase is an important constituent of nucleic acids and cell membranes, a major constituent of the structural components of skeletal tissues, and is directly involved in all energy-producing cellular reactions. Thus, it is an essential nutrient for growth, skeletal development, and reproduction of fish
Phytase effectively increases phosphorus availability of soybean meal, but less information is available on protein and amino acid utilization. Better protein economy of plant-based aquafeeds by phytase would increase the interest of the feed industry towards this relatively new feed supplement.
Advantages of phytase
- As the phosphorus bound in phytate becomes available as nutrient due to the addition of phytase, the inclusion of inorganic phosphorus such as fishmeal can be drastically reduced.
- The phytase reduces the release of nutrients into the environment by making the bound phosphorus available to the fish for growth – so it is incorporated into the fishes body instead.
- Phytase added to the diets improves protein and amino acid digestion in fishes.
- Phytase can improve the metabolizable energy of feeds by breaking down the phytate-lipid complex.
- Cheaper plant-based protein sources can be substituted for fishmeal lowering feed costs.
- Phytase added diets have been shown to have a higher feed intake, growth and better food conversion efficiency than control diets.
- Phytase reduces phosphorus load in their fecal matter of fishes and shrimps.
- Phytase improves phosphorus and protein digestibility.
Feeding enzymes to shrimps and fishes are one of the major nutritional advances in the aquaculture sector since last few years. Exogenous enzymes are now extensively used throughout the world as additives in animal diets. Also, supplementation with enzymes can help to eliminate the effects of antinutritional factors and improve the utilization of dietary energy and amino acids, resulting in improved performance of fish/shrimps
Factors contributing to use of Enzymes:
- Increase need for quality food grain for fish/shrimp
- Increase need for quality animal products /by-products
- Search for alternate sources of food with better nutritive value
- Economic margins(reduced cost: benefit-cost )
- Quick realization of profits
- Rise of environmental awareness
Establishing a healthy gut is the key to animal health and performance. Probiotic solutions are a sustainable alternative to antimicrobial compounds, as the latter has led to the development of resistance among bacterial populations. Great care must be taken in the selection of probiotic strains since it is essential to ensure that bacteria are beneficial to the host and able to thrive in the gut and aquatic environment. Lactic acid producing bacteria, e. g. Enterococcus faecium, have been the focus of much interest. Combined with other beneficial bacteria, multi-species products have proven that it is possible to provide synergistic bacteria with complementary modes of action to enhance health and zootechnical performances of cultured aquatic species.
Probiotics and their benefits
There is growing interest in the use of beneficial bacteria, probiotics, as an alternative strategy to antimicrobial compounds for disease prevention and control in aquaculture. These naturally occurring bacteria exert their beneficial effects on the host by modifying the microbial community associated with the host, by ensuring improved use of the feed or enhancing its nutritional value, or by enhancing the host response towards disease. At the animal level, probiotics improve the growth and survival of fish and shrimp by modifying the host-associated or ambient microbial community.
Bacteria subtilis grow efficiently with low-cost carbon and nitrogen sources, because its enzymes are very efficient breaking down a great variety of proteins, carbohydrates, and lipids from animal and vegetable origin, into their constituent units
The enzymes also degrade organic accumulated debris from shrimp/fish cultures inducing ponds bioremediation and consequently the prevention of viral and bacterial diseases . On the other hand, the antimicrobial activity of Bacillus is greatly determined by their ability to produce antibiotics, principally from peptide origin. There were identified 795 antibiotics from Bacillus species. B. subtilis is the genus most productive species devoting 4-5% of its genome to their synthesis, producing 66 antibiotics. Furthermore, Bacillus subtilis is Generally Recognized as Safe (GRAS) by the FDA, meaning this bacterium is not harmful to animals or humans. Taking into account beneficial properties of B. subtilis, this bacterium is a potential probiotic candidate to be considered in “Functional Feeds” of crustaceans and fishes
Feed application of probiotics for intestinal health
A well-established intestinal microflora is crucial for the growth and health of the animal since the microflora has impacts on:
- The prevention of pathogenic infections,
- The integrity and function of digestive organs,
- The development of the immune system
- Thus, the management of the gut flora is important for the ability to prevent infections with enteric pathogens and to guarantee a well-functioning and effective digestion of nutrients that result in good growth performance parameters.