Synthesis of L-methionine-loaded chitosan nanoparticles for controlled release and their in vitro and in vivo evaluation.

Therapeutically popular controlled release-enabling technology has forayed into the nutrition sector. Polymer coated forms of L-methionine used in soy protein diets, and its intermediate metabolite, S-adenosyl-L-methionine, used in myriad of medical conditions have proved more efficacious over (highly catabolized) free forms. In this premier study, L-methionine-loaded chitosan nanoparticles (M-NPs) were synthesized using ionic gelation method and their efficacy was evaluated. Biophysical characterization of the NPs was done using a Nanopartica SZ 100 analyser, transmission electron microscopy, and Fourier transform infrared spectroscopy. The M-NPs were spherical and smooth and 218.9 ± 7.4 nm in size and in vitro testing confirmed the controlled release of methionine. A 60-days feeding trial in L. rohita fish fingerlings was conducted. A basal diet suboptimal (0.85%) in methionine was provided with one of the supplements as under: none (control), 0.8% chitosan NPs (0.8% NPs), 1.2% L-methionine (1.2% M) (crystalline free form), 0.6% M-NPs and 1.2% M-NPs. While the addition of 0.6% M-NPs to the basal diet complemented towards meeting the established dietary requirement and resulted in significantly highest (P < 0.05) growth and protein efficiency and sero-immunological test scores (serum total protein, serum globulin, serum albumin: globulin ratio, phagocytic respiratory burst/NBT reduction and lysozyme activity), 1.2% supplementation in either form (free or nano), for being 0.85% excess, was counterproductive. Liver transaminases and dehydrogenases corroborated enhanced growth. It was inferred that part of the methionine requirement in nano form (M-NPs) can confer intended performance and health benefits in animals relying on plant proteins-based diets limiting in this essential amino acid. The study also paves the way for exploring chitosan NPs-based sustained delivery of amino acids in human medical conditions.

Expression of Growth and Hunger Related Genes and Physio-Biochemical Responses in Labeo rohita (Hamilton, 1822) Fed with Lysine and Betaine.

BACKGROUND/AIMS: The growth promoting effect of lysine and betaine as well as the expression of candidate genes reflecting their efficacy, such as ghrelin, leptin, Growth Hormone Secretagogue Receptor (GHS-R), Insulin like Growth Factor (IGF- 1) and Growth Hormone Releasing Hormone (GHRH) was examined in Labeo rohita fingerlings. METHODS: One hundred eighty healthy juveniles from a homologous population were randomly distributed to 15 rectangular tanks of 150 litres capacity. The experiment was carried out for 60 days with five treatment groups consisting T1 (0.25% Betaine), T2 (0.5% Betaine), T3 (0.75% Lysine) and T4 (1.5% Lysine) and control group. The experiment was carried out for 60 days with five treatment groups consisting T1 (0.25% Betaine), T2 (0.5% Betaine), T3 (0.75% Lysine) and T4 (1.5% Lysine) and control group. At the end of trial, the growth parameters such as weight gain, SGR, PER were estimated from the weight of the triplicate groups. The digestive, metabolic and antioxidant enzymes were analysed using spectrophotometric methods. The intestine, brain and liver were sampled from the treatments and expression of different genes ghrelin, leptin, GHSR, IGF-1 and GHRH was also performed by realtime PCR. RESULTS: A significant (P<0.05) increase in weight gain, SGR, PER and lowest FCR was found in T4 group which was significantly (p < 0.05) different from other experimental groups. The highest mRNA expression levels of expression were found in T4 group which was similar to that of ghrelin gene mRNA of T2 group. The significantly (p<0.05) highest GHSR, GHRH and IGF-1 gene expression levels were found in T4 treatment group compared to other groups. CONCLUSION: The present study reveals that the lysine and betaine stimulate growth and expression of ghrelin GHRH, GHS-R and IGF-1 genes. The increase of IGF-I mRNA expression with lysine and betaine supplementation revealed that these compounds act as growth modulators. However, lysine was found to be a more potent modulator of growth compared to betaine.