جستجوی مقالات مرتبط با کلیدواژه « Dry Feed » در نشریات گروه « شیلات »

The larviculture of fish and shellfish is inevitably dependent on live food such as Artemia and one of the most important issues in rearing Artemia is the food supply. Artemia culture is mainly dependent on freshly prepared unicellular algae, which is not accessible easily. This research focused to prepare a dry feed that can support the survival and growth of Artemia and improve its resistance against pathogenic bacteria. The nauplii of Artemia were fed seven feeding treatments, including the control diet (algae + yeast) and six experimental dry feed containing different levels of probiotic bacteria. The results showed that Artemia fed a diet containing 10% algae+1.25% probiotic bacteria performed slightly better in terms of growth, but significantly higher survival and increased alkaline protease activity was detected compared to control. The lipase activity was significantly higher only in Artemia fed 5% algae + 0.625% probiotic bacteria, and the highest Amylase activity was detected in the control group. The activity of the antioxidant enzymes superoxide dismutase (SOD), Glutathione reductase (GRed), Glutathione peroxidase (GPx) and Malondialdehyde (MDA) presented a significant increase as a function of culture time and probiotic administration. The challenge with the pathogen resulted in significantly higher survival in all tested life stages of Artemia (nauplii, juvenile, and adults) in negative and positive controls compared to the control diet group. It is concluded that pathogen induces an oxidative stress response in almost all stages of Artemia growth and probiotic bacteria Bacillus coagulans and B. subtilis protects Artemia when challenged with Vibrio anguillarum by enhancing immune responses.

Influence of three different stocking densities, vitamin C supplementation of Daphnia spp. and feeding practice (i.e. mechanical, hand) on the success of dry feed habituation of pond reared pikeperch juveniles was investigated through one month trial. Pond reared pikeperch juveniles were harvested 42 days post-fertilisation (mean individual weight 1.1 ± 0.3g) and stocked into the experimental recirculation system. For the stocking density trial, fish were stocked in three different initial densities of 0.5, 1 and 1.5 fish L-1, while the trial on live food supplementation and feeding practice was performed with two two-group comparisons with one common control treatment. All treatments were performed in 3 replicates. Analysis of variance did not reveal any significant differences in the assessed parameters between the tested stocking densities. However, Pearson correlation for the habituation success was strong in the course of increased density (r2 = 0.829, p = 0.006). Vitamin C supplementation led to increased survival, habituation success and growth, although the differences were not significant (p > 0.05). Similarly, there were no significant differences between the hand and mechanical feeding in the habituation success (p = 0.860). Based on the results of present study and previous results reported for habituation of pikeperch and walleye pond nursed juveniles, stocking densities of 4 to 8 fish L-1, feeding with dry feed with worms supplied manually and possible enrichment with vitamin C of the given food could be suggested for the successful commercial pikeperch dry feed habituation.