Effect of a New Feed Daphnia magna (Straus, 1820), as a Fish Meal Substitute on Growth, Feed Utilization, Histological Status, and Economic Revenue of Grey Mullet, Mugil cephalus (Linnaeus 1758)

Abstract

The formulator of aquatic diets is part of a continuous search for alternative protein sources instead of depreciated fish meal. The utilization of zooplankton as a feed ingredient is an interesting trend due to their high-quality protein content and abundance of essential nutrients. The current study aims to investigate the effects of partial and total replacement of fish meal (FM) by Dahpnia magna meal (DMM) on growth performance, feed utilization, histological, and economic status of mullet, M. cephalus, larvae. In addition to the control diet, 100% FM, D0, four diets containing DMM at different levels were used: 25% (D25), 50% (D50), 75% (D75), and 100% (D100) replacement of fish meal. A total of 300 larvae (0.097 ± 0.001 g) were equally divided into five groups (three replicate per each group) at a density of 200 larvae m−3. The aquariums were renewed at a rate of 30% daily. During the 60-day experimental period, all larvae were fed their respective diets at a level of 20% of live body weight, five times a day (9.00 a.m., 12.00, 15.00, 18.00, and 21.00 p.m.). The results indicated that compared to D0, fish fed D75 recorded the highest significant value of growth, and feed utilization parameters, while fish fed D100 achieved the lowest feed cost and incidence cost, and the highest profit index and economic efficiency ratio. A strong correlation was reported among weight gain, feed conversion ratio and fish meal replacement with DMM; R2 = 0.94 and 0.91, respectively. The fit regression model representing mullet response to FM replacement with DMM is a poly-nominal regression model with maximum response at 75–100%. The histological investigation of the intestine revealed an improvement of histomorphometric indices and goblet cell number with increasing DMM inclusion levels. These findings confirmed that 75% to 100% partial substitution of FM with DMM is the ideal replacement for mullet, M. cephalus, larvae for improving fish growth performance and feed utilization.

Growth Performance, Feed Utilization, Gut Integrity, and Economic Revenue of Grey Mullet, Mugil cephalus, Fed an Increasing Level of Dried Zooplankton Biomass Meal as Fishmeal Substitutions

“…Accordingly, ZBM could totally replace FM without negative impacts. In contrast, daphia meal as an FM replacer showed a quadratic regression trend and the best growth performance criteria were observed at 75% in the diet of grey mullet [33].…”

“…Other studies have also found that replacing FM (control diet contained 35% FM) with zooplankton meal up to 100% significantly improved growth performance, PER, and FCR of seabass, Dicentrarchus labrax, fingerlings [31]. In addition, Dahpnia magna meal as an FM alternative in the diet (control diet contained 18% FM) of grey mullet larvae could replace up to 75% of FM, which recorded the best growth and feed utilization parameters [33]. The barramundi, Lates calcarifer, fingerlings fed diets containing 5-10% daphnia meal have high immune surveillance and disease resistance compared to the control group [46].…”

“…Overall, this research study found that dietary FM could be replaced by ZBM up to 100% in grey mullet juvenile diets, with positive effects on growth performance and feed consumption, thus improving economic efficiency. In the same vein, the replacement of FM with Daphnia meal improved the ECR by 14.88% and 15.91% with 75 and 100% replacement levels, respectively [33]. One of the greatest impacts of replacement studies is the improvement of economic visibility of the diet, among other goals.…”

“…Previously, it was confirmed that Catla catla fry fed with different zooplankton, such as Copepoda, Thermocyclops decipiens, Crustacea, Moina micrura, and Daphnia spp., had higher protein, carbohydrate, and lipid content [20,54]. Abo-Taleb, et al [33] reported that the use of Dahpnia magna meal replacing FM at a level of 75% significantly improved the protein and lipid contents of grey mullet. Carcass protein, lipid, and nutrient digestibility were improved in the juvenile of Australian freshwater crayfish, Cherax destructor, fed on different protein sources (meat, snail, soybean, yabby, and zooplankton) [55].…”

“…The study of Sharahi, et al [32] revealed that the replacement of FM with gammarus meal up to 20% significantly improved different growth performance criteria and feed utilization of Siberian sturgeon, Acipenser baerii. In addition, the use of Dahpnia magna meal as an FM alternative in the diet of grey mullet showed a quadratic regression trend in terms of growth and feed utilization, with the best replacement level at 75% of FM [33]. The previous studies showed that the total zooplankton meal could replace 100% of FM; however, using individual types of zooplankton (daphnia or gammarus) partially succeeded in replacing FM in the aquatic diet.…”