Effects of arachidonic acid supplementation in maturation diet on female reproductive performance and larval quality of giant river prawn (Macrobrachium rosenbergii)

Abstract

The giant river prawn (Macrobrachium rosenbergii) is one of the most farmed freshwater crustaceans in the world. Its global production has been stalling in the past decade due to the inconsistent quality of broodstock and hatchery-produced seeds. A better understanding of the role of nutrition in maturation diets will help overcome some of the production challenges. Arachidonic acid (20:4 n-6, ARA) is a fatty acid precursor of signaling molecules important for crustacean reproduction, prostaglandins E and F of the series II (PGE2 and PGF2α), and is often lacking in maturation diets of shrimp and prawns. We examined the effects of ARA in a combination of different fish oil (FO) and soybean oil (SO) blends on females’ reproductive performance and larval quality. Adult females (15.22 ± 0.13 g and 11.12 ± 0.09 cm) were fed six isonitrogenous and isolipidic diets containing one of two different base compositions (A or B), supplemented with one of three levels of Mortierella alpine-derived ARA (containing 40% active ARA): 0, 1 or 2% by ingredient weight. The two base diets differed in the percentages of (FO and SO with diet A containing 2% SO and 2% FO and diet B containing 2.5% SO and 1.5% FO, resulting in differences in proportional contents of dietary linoleic acid (18:2n-6, LOA) and docosahexaenoic acid (22:6n-3, DHA)). After the eight-week experiment, prawns fed diet B with 1 and 2% ARA supplement (B1 and B2) exhibited the highest gonadosomatic index (GSI), hepatosomatic index (HSI), egg clutch weight, fecundity, hatching rate, number of larvae, and reproductive effort compared to those fed other diets (p ≤ 0.05). Larvae from these two dietary treatments also had higher tolerance to low salinity (2 ppt). The maturation period was not significantly different among most treatments (p ≥ 0.05). ARA supplementation, regardless of the base diet, significantly improved GSI, HSI, egg clutch weight and fecundity. However, the diets with an enhanced ARA and LOA (B1 and B2) resulted in the best reproductive performance, egg hatchability and larval tolerance to low salinity. These dietary treatments also allow for effective accumulation of ARA and an n-3 lcPUFA, DHA in eggs and larvae.

Role of Arachidonic Acid and COX Inhibitors in the Regulation of Reproduction in Freshwater Crab Oziothelphusa senex senex

“…Injection of arachidonic acid significantly induces maturation, in shrimp to Penaeus semisulcatus at a dose of 5 μg/g body weight and 10 μg/g body weights [35]. Earlier it was reported that arachidonic acid supplementation through diet significantly promotes reproductive performance in tank domesticated Penaeus monodon [36], in Daphnia magna [37] and improved gonad somatic index, hepatosomatic index, egg clutch weight and fecundity in prawn, Macrobrachium rosenbergii [38]. In several fishes, also Arachidonic acid supplementation increases reproduction [39][40][41][42].…”

Dry or wet? What is the best choice to determine gonadosomatic and hepatosomatic indexes in females of Macrobrachium amazonicum ?

“…Only the hepatopancreas of females in the final stage (V) in both phenotypes showed a significant decrease in water content. This is associated with increased lipid accumulation in this organ during stage V (final stage), which constitutes the final energy reserve for ovary maturation (Haefner & Spaargaren, ; Kangpanich et al, ; Soonklang et al, ; Spaargaren & Haefner, ). Franceschini‐Vicentini et al () and Ribeiro, Papa, Vicentini, and Franceschini‐Vicentini (), when analysing the histological and ultrastructural aspects of the hepatopancreatic tubules of M. amazonicum , identified five epithelial cell types: E (embryonic), F (fibrillar), B (blister‐like), R (resorptive) and M (midget) cells.…”

“…After the identification of the prawns according to Pillegi (), female carapace length (CL—distance between the posterior margin of the ocular orbit and the mid‐point of the posterior margin of the carapace) was measured with an analogic caliper (0.02 mm) and the ovarian stage was initially assessed by the colour and size of the ovary observed through the exoskeleton (Chang & Shih, ; Kangpanich et al, ). Immediately after these procedures, all animals were dissected and analysed.…”

“…Initially, the ovaries are colourless or translucent and occupy a small region in the cephalothorax of immature females (Figure a). In mature females, the ovaries become voluminous with an intense greenish coloration and are easily observed through the carapace in some species (Chang & Shih, ; Kangpanich, Pratoomyot, Siranonthana, & Senanan, ; Paschoal & Zara, ; Soonklang et al, ) (Figure e).…”

“…These processes are executed in specific pathways by each of their five cell types: E (embryonic), F (fibrillar), B (blister‐like), R (resorptive) and M (midget) cells. In addition to performing these functions, the hepatopancreas is the largest lipid storage organ in crustaceans and plays a key role in the development of the reproductive system, and, consequently, in reproduction (Adiyodi, ; Adiyodi & Adiyodi, ; Al‐Mohanna & Nott, , , ; Al‐Mohanna, Nott, & Lane, , ; Kangpanich et al, ).…”