Proximate, minerals, carotenoid and trypsin inhibitor composition in the exoskeletons of seafood gastropods and their potentials for sustainable circular utilisation.

Periwinkle shells of Tympanotonus fuscatus, Pachymelania aurita, and Thais coronata were analyzed for their proximate composition, nutritionally significant minerals, trypsin inhibitors, and carotenoids. The mean values obtained were compared using an ANOVA test. The results showed that T. fuscatus had the highest mean moisture content of 0.96 ± 0.14% and a mean value of 0.49 ± 0.13% for crude fibre but was not significantly different (P > 0.05) from P. auritus. The crude protein and fibre content of T. fuscatus was significantly higher (P < 0.05) than other periwinkle samples. T. coronata had the highest mean total ash content and was significantly different (p < 0.05) from other periwinkle samples. T. fuscatus had the highest mean value for Mg (0.32 ± 0.03 mg/kg) and differed significantly (P < 0.05). The mean Ca content of P. aurita was not significantly different (P > 0.05) from that of T. coronata. The mean values of CaCO3 in T. fuscatus, P. aurita, and T. coronata were 57.20 ± 2.46, 59.50 ± 3.23, and 62.36 ± 1.56 (mg/kg), respectively. T. coronata was significantly different (P < 0.05) from other periwinkle samples. The mean values of carotenoids in T. fuscatus, P. aurita, and T. coronata were 7.17 ± 2.14, 18.00 ± 5.27, and 11.20 ± 3.60 (mg/kg), respectively, and P. aurita was significantly different (P < 0.05) from other periwinkle samples. T. fuscatus and P. aurita had shells with significant amounts of trypsin inhibitor (23.30 ± 4.50 mg/kg and 22.90 ± 14.10 mg/kg, respectively), making them less suitable for livestock feed. In contrast, T. coronata had a lower mean value of 11.80 ± 7.19 mg/kg for trypsin inhibitor, making it an excellent addition to livestock feed. The low crude fibre and fat contents of the periwinkle samples in this study make them suitable for processing complementary foods, especially for hypertensive patients. The high percentage of CaCO3 in periwinkle shells makes them a probable source used in the production of slurry for chromatography. The findings suggest that periwinkle shells contain specific minerals that can be applied in numerous industries. Increased use of these gastropod shells will result in successful application in product creation and a sustainable bio-circular economy.

Chemometric estimation of captured Farfantepenaeus notialis, Pérez-Farfante 1967 (Crustacea: Penaeidae).

BACKGROUND: Chemometrics can be used to analyze a wide range of food products for authentication, quality control, differentiation and the determination of nutrition quality. Owing to the scarcity of studies relating to the intrinsic physico-chemical characteristics of penaeid shrimps caught on the Nigerian coast, the aim of this research was to estimate the energy-supplying nutrients, mineral elements and functional characteristics of Farfantepenaeus notialis from the Lagos Lagoon. METHODS: The proximate composition was determined using the AOAC method while the energy-providing nutrients were multiplied by the Atwater factors. The samples were digested in HNO3/HCl for mineral determination and the functional properties were estimated using optical measurements. RESULTS: Higher concentrations of moisture, crude protein, crude fat, and carbohydrate were recorded in the flesh while crude fibre and total ash were higher in the exoskeleton samples. The flesh had higher total metabolisable energy (1524 kJ 100 g-1) and utilizable energy due to protein (36.49 kJ). All the investigated minerals (Ca, Mg, K, P and Na) were more concentrated in the exoskeleton. In both samples, Na/K and Na/Mg ratios were within acceptable ideal ranges of 1.4-3.4 and 2-6, respectively. All values of the MSI (calculated) were lower than their comparative standard index values, having positive contrasts in both exoskeleton and flesh samples. The exoskeleton sample had better functional properties, but the flesh sample was higher in swelling strength. CONCLUSIONS: In addition to good flesh quality, F. notialis contains considerable amounts of energy-providing nutrients. As the content of fibre is very low, F. notialis may be ideal as a weaning food for children.

Role of Intestinal Helminth Parasite of Macrobrachium vollenhovenii-Cucullanus sp. in Host Metal Accumulation in Epe Axis of the Lekki Lagoon, Lagos, Nigeria.

This paper assesses the role of intestinal helminth parasite of Macrobrachium vollenhovenii on host metal accumulation in Lekki lagoon, Lagos, Nigeria. Lead, zinc, copper, chromium and iron concentrations were determined in water, sediment, intestinal parasite, intestine of infected and non-infected prawns. Intestinal nematode parasite Cucullanus sp. was identified. Pb and Cr were not detected in the water and sediment. The sediment had higher concentrations of the metals than the water medium, and exceeded the WHO limits for Zn, Cu and Fe. Cucullanus sp. accumulated Zn 19 times, Cr several thousand times more and Fe 11 times more than the host intestine (wet wt). This parasite could have accumulated these metals from its host, reducing the concentration of these metals in the tissues of the infected prawns compared to non-infected ones. The infected and non-infected prawns accumulated Zn and Fe several times more than the water medium. The parasite influenced metal accumulation in the host tissue and pose ecological risk.

Effect of salinity on survival and growth of blue crab, Callinectes amnicola from Lagos Lagoon, Nigeria.

The effect of salinity on the survival and growth of Callinectes amnicola (De Rocheburne) from the Lagos Lagoon, Nigeria was monitored in the laboratory for 22 weeks. The crabs were euryhaline and tolerated a salinity range of 5 to 25 per thousand and had 90% survival at 15 and 20 per thousand. The highest gain in weight (173.0%) and carapace width (56.1%) was obtained at salinity of 15 per thousand. The highest specific growth rate (1.98) was obtained at 15 per thousand, while the lowest specific growth rate (-0.28) was recorded at 35 per thousand. The condition factor of the crabs showed a fairly consistent pattern at the different salinity levels with values ranging from 5.7 to 7.3. Complete moulting was obtained at salinity of 15 per thousand in the 12th week of the experiment. The crab with carapace width of 6.8 cm increased to 8.1 cm (19.1%) after moulting.