Particulated Microalgae Composite (PMC) As Substitute For Live Microalgae In Culture Of Juvenile Manila Clam Ruditapes Philippinarum (A. Adams And Reeve, 1850): A Feasibility Analysis

Abstract

To evaluate the feasibility of particulated microalgae composite (PMC) as live microalgae substitute in artificial breeding of Manila clam Ruditapes philippinarum, effects of replacing Dicrateria inornata with partial or total PMC on the growth, digestive enzyme activities, nutritional ingredient composition and microbial composition in faeces of juvenile clams were investigated. The results showed that 50 and 100% PMC replacement did not affect the mean shell length, mean body weight and survival rate of juvenile clams (p>0.05). Juvenile clams fed with 100% PMC replacement had higher lipase and pepsin activities than those fed with 100% D. inornata (p<0.05), while 50% PMC replacement only increased lipase activity (p<0.05). Essential amino acid (EAA) and polyunsaturated fatty acid (PUFA) contents exhibited no obvious differences between clams fed with and without PMC replacement (p>0.05). Significant increase in delicious amino acid contents (p<0.05) was observed with 100% PMC replacement. PMC replacement did not affect the diversity of dominant phyla in faeces, but the abundance of each dominant phylum. Similar relative abundance of faecal bacteria was observed when D. inornata was replaced with 50 and 100% PMC. PMC appeared to be a potential substitute for microalgae in artificial Manila clam breeding.

Impact of ocean acidification on the physiology of digestive gland of razor clams Sinonovacula constricta

“…The growth of aquatic animals depends on nutrient utilization to a great extent, and digestive enzymes play an important role in nutrient digestion (Liang et al, 2021). Their activity directly reflects the digestive capacity and nutritional status of aquatic animals (Furne et al, 2005).…”

“…The digestive gland of three razor clams from each replicate was mixed as one sample to determine activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), and glutathione (GSH), and digestive enzymes, including amylase (AMS) and lipase (LPS). The preparation method was based on our previous study (Liang et al, 2021). In brief, digestive gland samples were homogenized three times with physiological salt solution (1:9W/V) in ice water for 30s, using an electric mixer at 6,000 rpm.…”

“…The antioxidant defense system can remove excessive ROS produced by biological organisms due to environmental changes and prevent cells from oxidative damage (He et al, 2021). Digestive enzymes play an important role in nutrient digestion, and their activities can directly reflect the digestive capacity and nutritional status and ultimately translate into the growth performance of marine bivalves (Liang et al, 2021). However, in previous studies, most bivalves were directly exposed to acidified seawater, while most of the bivalves in the natural environment lived in the seabed sediment.…”