Pre-breeding Diets in the Seahorse Hippocampus reidi: How Do They Affect Fatty Acid Profiles, Energetic Status and Histological Features in Newborn?

Seahorses (Hippocampus spp.) are exceptional marine species considering their reproductive patterns and other features. Due to the iconic characteristics of these fishes, aquarium trade, and research efforts have increased in the last years. Consequently, novel rearing techniques have been developed; however, there is a need for improvements on a series of issues, namely reproduction success enhancement. The tropical species Hippocampus reidi is the most traded seahorse but many aspects of breeding and its impact on the quality of neonates are still poorly understood. In the present study, we assessed the effects of two pre-breeding diets on newborn quality and viability considering biochemical characteristics, energetic status, and ultrastructural aspects of muscular tissue. During the whole pre-breeding season (5 months), the breeders were fed on one of the following diets: M0 (adult non-enriched Artemia) and M5 (adult non-enriched Artemia + mysidaceans). From the onset of the reproduction period, all breeders were fed for 6 months on diet M5. Breeding success and energetic status (ATP, total adenylic nucleotides, AEC, and NAD) of newborns resulted considerably enhanced in treatment M5. However, initial differences in neonates quality did not affect further newborn performance (survival and growth until day 7 after male’s pouch release) while gaining access to high-quality preys (copepods). Besides, morphological alterations in muscle tissue were not observed. The reproduction in the species followed a capital–income continuum pattern characterized by an initial mixed capital-income period (until 70–100 days since the onset of the breeding season) followed by an income breeding period with progressive exhaustion of body reserves, especially in M0-newborns. Interestingly, the effects of pre-breeding diets were also noticed in the second half of the breeding period. Our results seemed to indicate that the requirements in essential fatty acids in H. reidi are lower than in other seahorse species (e.g., Hippocampus guttulatus). Globally, the results achieved revealed that high-quality pre-breeding diets enhanced reproduction success and would likely result advantageous to improve newborn endurance in conditions of moderate starvation or sub-optimal feeding.

Study on Sex Determination and Impact of Sex Ratio to Reproduction Success in Black Soldier Fly

Black soldier fly (BSF) (Hermetia illucens) is an insect spe-cies utilized as the converter of organic wastes into biomass applicable as a potential replacement of protein and lipid sources of animal feed and other industrial use. The limiting factor for the sus-tainability of this activity is the number of eggs produced as all processes started from the egg. Variable of quality of the substrate eaten during the larval stage and the proportion of males and fe-males are among the decisive factors for egg production. The pur-poses of this study were to understand the impact of the substrate to the production of a particular sex, to developed a simple method by comparing the weight and size of the pupae to distinguished between male and female, and to find the best sex ratio to produce the highest number of eggs. In this study, two types of substrates (balance proportion of macronutrient and high in protein and lipid were applied as feeding material for larvae. The weight and length of each pupa produced were measured and the pupae kept inside separated containers to find the morphological differences between male and female pupae. Adult insects produced from pupae then used for study on the effect of sex ratio on reproduction success. The adults kept inside 1 x 1 x 1 m screen cages with 3 groups of sex ratio (male : female) which were 50%:50% (P1), 60%:40% (P2), and 40%:60% (P3). The probability of sex was analyzed by logistic regression while the number of eggs estimated by the weight of the egg batch. The result showed substrate used in this study is not affect the sex ratio of adult flies, weight of pupae as the best predictor for sex of the adult flies, and the best ratio of male and female for egg production was 40:60.