Banca de DEFESA: ALEX SILVA MARQUEZI

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ALEX SILVA MARQUEZI
DATE: 18/08/2023
TIME: 14:00
LOCAL: Web Conferência - Google Meet: https://meet.google.com/bkz-khim-drx.
TITLE:

Effects of dietary microalgae supplementation on immune response and resistance to white spot virus challenge associated with heat stress in Pacific white shrimp raised at suboptimal temperature.

KEY WORDS:

Aurantiochytrium sp.; Litopenaeus vannamei; White spot syndrome; feed additive; winter diet.

PAGES: 45
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUMMARY:

This study aimed to evaluate the resistance and the hemato-immunological parameters of the Litopenaeus vannamei to the white spot syndrome virus (WSSV) challenge associated with thermal stress, after food supplementation with 0, 1, 2, 3 and 4% of Aurantiochytrium sp. microalgae inclusion. The shrimps were raised in 400L tanks, in triplicate, over a period of 63 days under suboptimal temperature (22°C), in a clear water system. The animals were fed four times a day and the amount of food was calculated by the programmed feed conversion method. For the WSSV challenge, 14 animals per treatment were transferred to 50L tanks, acclimated for 48h, and then orally infected with a total viral load of 2,6x106 per gram of animal. After infection, the shrimps were kept for 108 h under suboptimal temperature (22°C), followed by 12 h of temperature increase until reaching 28 °C (0,5 °C h-1) and 48 h more under optimal temperature (28°C), totaling 7 days. The mortality was monitored every 3 h throughout the entire infection. The hemolymph samples were collected after 96 h and 168 h after the viral infection. The data were tested for normality and homogeneity to meet ANOVA and MANOVA requirements. The treatments with 3% and 4% of Aurantiochytrium sp. supplementation showed lower mortality during the period under suboptimal temperature and at the end of the bioassay only the 4% level resulted in lower mortality (p<0.5), but no difference was observed in the hemato-immunological parameters between treatments (p>0,05). When using the multivariate analysis to evaluate the different parameters and conditions, it was observed that during the period under a temperature of 22°C the T0 differed from the other treatments, due to the significant increase in mortality in this period, as well as the reflections on the PO activity and the agglutination titer. Thus, the results suggest that Aurantiochytrium sp. supplementation, in particular the 4% level, may be satisfactory for shrimp production under suboptimal temperature and in mitigating the effects of stress due to thermal variation and viral infection.

COMMITTEE MEMBERS:
Externa à Instituição - SCHEILA ANELISE PEREIRA - UFSC
Presidente - 2613308 - DELANO DIAS SCHLEDER
Externo à Instituição - Giovanni Mello - EDESC