Efficacy of moringa, Moringa oleifera (Lamark, 1785) and turmeric, Curcuma longa (Linnaeus, 1753) as feed additives for giant freshwater prawn Macrobrachium rosenbergii (de Man, 1879) larvae

The present study investigated the effect of moringa and turmeric as feed additives in egg custard on the growth performance and survivability of giant freshwater prawn, Macrobrachium rosenbergii larvae. M. rosenbergii farming in Malaysia had been highlighted under National Key Economic Area (NKEA) to enhance economic activity. However, Malaysia's M. rosenbergii industry are still facing the problem of insufficient supply of good quality Post Larvae (PL). Thus, an effort to improve the quality of M. rosenbergii larviculture must be taken to fulfill the market demand and expansion of the industry especially in Malaysia. Therefore, in the present study, the effect of different egg custard formulations mixed with moringa and turmeric at different inclusion rates (1%, 3%, and 5% of turmeric and moringa, respectively), were studied on growth performance and survivability of M. rosenbergii larvae. The seven formulations were named as T1 (egg custard+1% turmeric), T2 (egg custard+3% turmeric), T3 (egg custard+5% turmeric), T4 (egg custard+1% moringa), T5 (egg custard+3% moringa), T6 (egg custard+5% moringa) and T7 (egg custard+1% moringa and 1% turmeric). Each treatment (n=1000) was carried out in three replicates, fed with the respective dietary treatment ad libitum three times a day and the growth performance of M. rosenbergii larvae was monitored for 30 days. Control treatment formulation (egg custard only) was obtained from Pusat Penetasan Udang Galah. Proximate analysis of egg custard formulations was done to determine dry matter, ash, fat, and crude protein. Texture analysis was carried out using colour and physical properties analysis, including bulk density, sinking velocity, water absorption index, and water stability. Growth parameters which were larvae stage index, day of first PL appearance, length, and weight as well as survivability were recorded. At the end of the experiment, the amino acid profile test proceeded with three treatments that showed the high growth performance of M. rosenbergii larvae. The findings indicate that the proximate analysis parameters except crude protein were significantly different at p<0.05. Next, the physical colours between all egg custard formulations are significantly different at p<0.05 on the colour lightness, the colour intensity in red and green, and the colour intensity in yellow and blue. Moreover, the physical properties of all egg custard formulations are significantly different at p<0.05 on the bulk density, sinking velocity, water absorption index, and water stability. However, the percentage of water stability is lower, around 26.67% to 29.78%. This indicates the nutrition in egg custard is quickly leaching and needs improvement. Concurrently, T7 treatment showed the highest larvae stage index of M. rosenbergii (mean±SEM) (10.6±0.13), followed by T6 (10.4±0.13) and control (10.2±0.11), while T6 treatment showed the highest growth performance based on weight and length of M. rosenbergii PL (mean±SEM) (31.72mg and 10.6±0.06mm), followed by T7 (31.05mg and 10.5±0.05mm) and control (30.94 and 10.5±0.07mm) respectively which were significantly different at p<0.05. The amino acid profile results on T6, T7, and control treatment showed six essential amino acids: histidine, arginine, threonine, isoleucine, phenylalanine, and tryptophan that were significantly different at p<0.05. T6 had the highest value on arginine, threonine, isoleucine, phenylalanine, tryptophan, and T7 on histidine, respectively. In conclusion, the findings suggested that T6 treatment is a potential feed for M. rosenbergii larvae based on the growth performance and nutrition content, but the feed required further testing at the commercial scale and improvement in terms of stability prior to commercialisation.