ARTICLE 68 FEED & ADDITIVE MAGAZINE August 2023 in soybean meal-based diets. Nucleotide supplementation improves feed intake, growth, immune responses, and disease resistance in species like Litopenaeus vannamei, Oreochromis mossambicus, Epinephelus malabaricus, and Rainbow trout. Synthetic mixes of IMP and AMP attract crabs and lobsters, increasing feed intake. D. AMINES Scavenging aquatic species, such as Indian River prawn and other fishes, are known to consume decaying matter. Biogenic amines like cadaverine and putrescine found in decaying material attract these species due to their resemblance to parent amino acids. These amines act as chemoattractants, incitants, and stimulants for feeding. However, trimethylamine oxide, creatinine, and guanidino compounds like glycocyamine and creatine have limited feed stimulation activity in certain species. A mixture of organic bases, including betaine, choline chloride, homarine-HCl, TMAO, TMA-HCl, and DMA-HCl, stimulates feeding when incorporated into feed pellets. The odor of amines in the feed or decaying material mimics food intake, resulting in increased feeding activity. Dimethylthetin acts as a taste stimulant in Dover sole, while other quaternary amines like homarine, betaine aldehyde, and trigonelline have no significant taste effect. E. SUGARS Sugars in fish can have varying effects on feed intake, acting as stimulants, deterrents, or indifferent taste substances. Certain sugars like D-glucose, sucrose, D-ribose, and D-fructose are highly palatable for rainbow trout, while others like D-galactose and D-xylose have no significant effect. However, in red sea bream, maltose and glucose were found to be ineffective in stimulating feed intake. A study involving different poecilids (Platy and Molly) tested 15 sugars and found that sucrose supplementation increased feed intake. Interestingly, there was a species-specific taste preference for sugars between Platy and Molly, indicating that taste preferences are highly specific to each fish species. F. ORGANIC ACIDS Organic acids are organic compounds with carboxyl groups and are produced through carbohydrate fermentation by bacteria under different conditions and metabolic pathways. In aquatic animals, organic acids have been observed to act as feed stimulants. For example, reactive amino-caproic acid has been found to increase feed intake in rainbow trout. Gamma amino butyric acid and L-Alpha-amino butyric acid were active at a 10-fold dilution in seabream, whereas succinic acid, malic acid, and citric acid were ineffective in stimulating feed intake. In tilapia, malic acid had no effect on feed consumption stimulation, while citric acid stimulated feed intake at a concentration of 0.01 M. Some organic acids like malic acid, alpha-keto-glutaric acid, and oxalic acid were highly palatable in certain fish species. However, the taste response to carboxylic acids varies among different fish species. Attraction to feed Feed İntake Utilization of nutrients Growth and health performance Sensation by fish chemoreceptors .. .. . Fish meal free feed Palability Organic Acids Betaines Free amino acids Sugars Nucelotides
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