Effect of the enrichment of n-3 HUFA in the larvae and breeders of the barber goby Elacatinus figaro

Author: Marcelo Roberto Pereira Shei (Currículo Lattes)
Supervisor: Dr Luís André Nassr de Sampaio
Co-supervisor: Dr Luis Alberto Romano

Abstract

The present work analyzed the effect of food supplementation with n-3 HUFA fatty acids on the reproductive and larvicultural performance of barber goby Elacatinus figaro, including also the description of the ontogeny of the immune system. For four months, two groups of breeders were fed with commercial fish feed and Artemia biomass enriched and not enriched with n-3 HUFA. Breeding animals fed both diets were able to spawn continuously, showing no significant differences for reproductive frequency (12.6 ± 0.7 and 12.0 ± 1.2 days) and egg volume (0.49 ± 0.01 and 0.48 ± 0.01 mm3). Fertility was higher in the treatment without the supplementation of n-3 HUFA (329 ± 36 and 517 ± 50 eggs/spawning).A second study evaluated the effect of supplementing the diet with n-3 HUFA on larval survival and growth. For that, newly hatched larvae were divided into two experimental groups, where one group was fed with non-enriched Brachionus plicatilis rotifers and the other group with rotifers enriched with n-3 HUFA. At seven days after hatching (dah), growth was greater in the group fed with enriched rotifers, but at 14 dah there were no more significant differences between groups (6.09 ± 0.62 and 5.69 ± 0.66 mm). At that time, although there were no significant differences, the survival of larvae fed with rotifers enriched with n-3 HUFA was three times greater (35.7 ± 3.1%) than the group that received non-enriched rotifers (11.1 ± 5.2%). For the description of the growth of the lymphoid organs,samples were collected periodically between 0 and 94 dah. The description was made through morphometric analyzes of the thymus and kidney and evaluation of the phenotypic expression (%/mm2) of CD3 and CD4 in these organs. At the time of hatching, it was possible to observe the presence of the kidneys (0.31 ± 0.01 mm) and the thymus (0.03 ± 0.03 mm), reaching 1.23 ± 0.15 mm and 90 ± 1.41 mm at 94 DAH respectively. As for CD3, the first phenotypic expression was found in the thymus at the time of hatching (71.25 ± 8.42%/mm2) and in the kidney from 6 DAH (0.02 ± 0%/mm2), at 94 DAH the expressions reached 90 ± 1.41 and 53.67 ± 1.53%/mm2 in the thymus and kidney, respectively. CD4 was initially expressed in the thymus at 3 DAH (1.33 ± 1.15%/mm2) and in the kidney at 12 DAH (5.33 ± 1.53%/mm2), reaching 22.00 ± 1.41 respectively and 44.00 ± 2.00%/mm2 at 94 DAH.

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