Nutrient allocation to eggs in female Argentinus shortfin squid, Illex argentinus using fatty acids as nutrient indicator

Fatty acids play a critical role in embryonic development of cephalopods. However, little information is available on the allocation of fatty acids to eggs during oogenesis, limiting our understanding regarding how these animals maximize reproductive performance in terms of energy and nutrient use. We explored the nutrients for egg production during maturation for Argentine shortfin squid (Illex argentinus (Castellanos, 1960)) by comparing the fatty acid profiles between the ovary and eggs in the oviducts. We detected 30 fatty acids in the ovary and eggs, of which 19 constituted more than 0.2% of the total fatty acid content. The overall fatty acids in the ovary varied significantly among maturity stages, while the eggs had a consistent amount of total fatty acids and relative amount of individual fatty acids. There were consequently significant differences in the fatty acid profiles between the ovary and eggs by maturity stage and in total. Additionally, eggs had more saturated fatty acids but less polyunsaturated fatty acids than the ovary. Cumulatively, our results reveal that this squid produces eggs with consistent levels of nutrients virtually regardless of how the nutrient profile of the ovary varies during maturation, providing insight into the egg production process relation to nutrient allocation.