Browsing by Subject "49892"
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Changes in mRNA expression of grouper (Epinephelus coioides) growth hormone and insulin-like growth factor I in response to nutritional status -
General and Comparative Endocrinology, 2006 - ElsevierGrowth hormone (GH) and insulin-like growth factor-I (IGF-I) are key links to nutritional condition and growth regulation in teleost. To understand the endocrine mechanism of growth regulation in grouper, we cloned the cDNAs for grouper GH and IGF-I and examined their mRNA expression during different nutritional status. Grouper GH cDNA is 936 base pairs (bp) long excluding the poly-A tail. It contained untranslated regions of 85 and 231bp in the 5'- and 3'-ends, respectively. It has an open reading frame of 612bp coding for a signal peptide of 17 amino acids (aa) and a mature hormone of 187aa residues. Based on the aa sequence of the mature hormone, grouper GH shows higher sequence identity (>76%) to GHs of perciforms than to GHs of cyprinids and salmonids (53-69%). Grouper preproIGF-I cDNA consisted of 558bp, which codes for 186aa. This is composed of 44aa for the signal peptide, 68aa for the mature peptide comprising B, C, A, and D domains, and 74aa for the E domain. Mature grouper IGF-I shows very high sequence identity to IGF-I of teleost fishes (84-97%) compared to advanced groups of vertebrates such as chicken, pig, and human (=<80%). Using DNA primers specific for grouper GH and IGF-I, the changes in mRNA levels of pituitary GH and hepatic IGF-I in response to starvation and refeeding were examined by a semi-quantitative RT-PCR. Significant elevation of GH mRNA level was observed after 2 weeks of food deprivation, and increased further after 3 and 4 weeks of starvation. GH mRNA level in fed-controls did not change significantly during the same period. Hepatic IGF-I mRNA level decreased significantly starting after 1 week of starvation until the 4th week. There was no significant change in IGF-I mRNA levels in fed-controls. One week of refeeding can restore the GH and IGF-I mRNA back to its normal levels. Deprivation of food for 1-4 weeks also resulted in cessation of growth and decrease in condition factor.
Efficacy of an inactivated vaccine and nutritional additives against white spot syndrome virus (WSSV) in shrimp (Penaeus monodon) -
The Israeli Journal of Aquaculture-Bamidgeh, 2011 - SIAMBAlthough the immune system of shrimps is not comparable to that of vertebrates, shrimps can acquire protection against pathogenic challenge by building up immunity. In this study, formalin-inactivated virus (FIV) was administered by injection, bath-immersion, or orally to determine levels of vaccination-mediated protection against the pathogenic white spot syndrome virus (WSSV). Diets supplemented with alfalfa, methyl sulfonyl methane (MSM), or wheat grass were provided with or without FIV. Shrimp injected with FIV and challenged 3, 15, or 30 days after vaccination had cumulative and relative survivals of 83%, 67%, and 33%, respectively. Survival of shrimp challenged by bath-immersion 3-45 days after vaccination by immersion was significantly higher than in the unvaccinated control. Orally vaccinated shrimp challenged by bath-immersion were partially protected up to 45 days after vaccination (cumulative survival 63.7%, relative 61.7%) but not til 60 days after vaccination (cumulative 8%, relative 3.2%). Survival of unvaccinated shrimp challenged by bath-immersion improved when shrimp were fed a diet supplemented with wheat grass or MSM, but not alfalfa. Survival was further enhanced when FIV was provided together with diets supplemented with wheat grass (cumulative 72.7%, relative 94.8%) or MSM (cumulative 73.3%, relative 96.3%).
Growth and production of milkfish (Chanos chanos) in brackishwater ponds: effects of dietary protein and feeding levels -
Aquaculture, 1995 - ElsevierThe most economical combination of dietary protein and feeding levels for milkfish culture in brackishwater ponds was determined. Milkfish juveniles (average weight, 5 g) were stocked at 7000/ ha and fed two diets containing 24% or 31% dietary protein at 2 or 4% of body weight. There was no interaction between feeding level and dietary protein on growth, feed efficiency, and energy assimilation of milkfish. This indicates that the response of milkfish to change in protein levels is not influenced by ration size. Regardless of protein levels, the final weight, weight gain, specific growth rate, and production of milkfish were significantly higher (α = 0.05) when fed at 4% body weight than at 2%. As culture progresses, differences in weights of fish fed varying protein levels were still insignificant. This could be attributed to the balanced amino acid profile of both diets. The higher growth at the 4% feeding level could be due to the higher amount of amino acids available for protein synthesis. Higher energy assimilated by milkfish at higher feeding rate demonstrates that energy supply also influences growth. Partial budgeting analysis shows that bigger profits can be earned by using a 24% protein diet with balanced amino acids at a feeding rate of 4% of body weight. The greater amount of feed given at higher rate can be compensated by faster growth and higher production.