Ontogenic development of digestive enzymes in bigfin reef squid (Sepioteuthis lessoniana)

Abstract

Bigfin reef squid (Sepioteuthis lessoniana) is an economically important exported aquatic animal in Thailand, but little is known about its husbandry, which needs to be clarified. In this study, the ontogenic development of the main digestive enzymes (pepsin, trypsin, chymotrypsin, lipase and amylase) was investigated within 30 days after hatching (DAH). Fertilized eggs of the wild cuttlefish were hatched and then distributed into four replicate aquaria assigned to varying collection times (0, 5, 10, 15, 20, 25 and 30 DAH). The development of pepsin suggests acidic digestion functionality at 5 DAH, and its specific activity was maintained over the studied period. Specific activities of the serine proteases, trypsin and chymotrypsin, fluctuated significantly with similar pattern, and appear to be the key enzymes contributing ontogenic changes in protein catabolism. The specific activity of lipase was relatively high at 0 DAH, dramatically increased by 5 DAH, and then appeared constant until the end of observations, suggesting important role in utilizing the lipid from yolk at hatching, as well as probably in sparing protein utilization. Dramatic increase in amylase specific activity occurred by 10 DAH after which the activity was constant until 30 DAH, suggesting the utilization of carbohydrate as energy evolves comparatively late. Findings from the current study could be used to manage nutritional protocols according to the digestive enzyme patterns, as well as to develop artificial diets for rearing S. lessoniana.

Optimal feeding frequency for bigfin reef squid (Sepioteuthis lessoniana)

“…The coefficients of variation of body weight and total length were not significantly affected by feeding frequency, but the trend gradually decreased with frequency. Feeding 4TD (23.77%) or 5TD (21.67%) in the current study significantly decreased the CV of weight from that of one‐month‐old bigfin reef squid fed 2TD (30.80%) from a prior report (Saekhow et al, 2018). Generally, juvenile squids grow fast and are very active in feeding behaviour (Nabhitabhata, 1995; Vidal et al, 2014).…”

“…The high SGR of this species, relative to other aquaculture species, is a valuable trait supporting its future aquaculture. However, high SGR has been observed from newly hatched stage until 30 days post hatching (13.4% BW/day) (Saekhow et al, 2018) or over 100 days of experimentation (12.0% BW/day) (Lee et al, 1994). For other species, SGR values 3.2–3.7% and 4.4% BW/day have been reported in Mexican four‐eyed octopus, Octopus maya (Aguila et al, 2007; Gallardo et al, 2020) and in California two‐spot octopus, Octopus bimaculoides (Solorzano et al, 2009).…”

Life in a fishbowl: Space and environmental enrichment affect behaviour of Betta splendens

“…One ornamental fish species, the Siamese fighting fish (Betta splendens), is aggressive to conspecifics so pet stores keep individual males isolated in small fishbowls around 0.5 L in volume (Figure 1). Producers keep individuals in volumes even smaller, with researchers recommending 150 mL for permanent holding (Saekhow et al 2018) and 80 mL for transport (Thongprajukaew et al 2023). Organisations such as People for the Ethical Treatment of Animals (PETA) consider this practice to be cruel, and have campaigned to end the practice of keeping Bettas in small bowls (The Herald 2009;PETA 2021).…”

Biochemical characterization of protein-digesting enzymes from viscera of bigfin reef squid (Sepioteuthis lessoniana) and implications for in vitro protein digestibility

“…The desirable characteristics of this squid for aquaculture include its large hatching size, tolerance to handling and confinement, short life span and rapid growth rate (Forsythe et al, 2001;Walsh et al, 2002). However, the mariculture of this species is limited by the difficulty of supplying an economic feed (Saekhow et al, 2018).…”

“…The proteinases from the hepatopancreas of wild Mexican four-eyed octopus exhibited maximum activity at pH 4, pH 9-10 and pH 10 for total proteinases, trypsin and chymotrypsin, respectively, while the optimal conditions for these enzymes obtained from gastric juice were pH 6, pH 8, and pH 7, respectively (Martinez et al, 2011). For bigfin reef squid, the ontogenic changes of protein-digesting enzymes (pepsin, trypsin and chymotrypsin) were investigated at pH levels of 2, 9 and 9, respectively, without optimizing the favored conditions (including pH and temperature) (Saekhow et al, 2018). Studying these digestive enzymes can help to understand the hydrolysis of main nutrients in the aquaculture of squid species (Ibarra-García et al, 2018).…”