The objective of the present study was to investigate the effect of varying crude protein (CP) levels on intake, growth performances and nutrient digestibility of Dorper lambs at pre- and post-weaning period. Twenty lambs at 7 days old with an initial body weight of 2.91 kg were individually penned and randomly assigned into four (4) dietary groups using a randomised complete block design. In Trial I, pre-weaning lambs were fed with creep feeding (CF) diet containing 14% crude protein (CP) as a control diet (CON14), 16% (CF16), 18% (CF18) and 20% (CF20) of CP for 84 days. Following Trial 1, the animals were fed with a growing ration (GR) diet for 96-day feeding trial. The diets consisted of 11% CP as a control diet (CON11), 14% (GR14), 16% (GR16) and 18% (GR18) of CP. The water was available ad libitum and the feed intake was measured daily by the difference of feed offered and refused. The increase of CP level resulted in a linear increase of dry matter intake (DMI), nutrient intake and average daily gain (ADG) in pre- and post-weaning lambs. The DMI (g/day) of lambs fed with CF20 (1059.92) was significantly higher (p 0.05) compared to those fed with CF16 (217.95). For post-weaning lambs, GR16 had significantly higher ADG than CON11 (43.14), but it was no difference with GR14 (72.94) and GR18 (69.41). However, increased CP level resulted in linear increase of DM, ash, organic matter (OM) and CP digestibility. The present finding suggested that the optimum CP level for pre- and post-weaning Dorper lambs in Malaysia was 16% and 14%, respectively.
Soybean lecithin is extensively used as the dietary supplementation of phospholipids in animal production. Soybean lecithin plays significant roles in aquafeed as growth promoter, feed enhancer, immunity modulator and antioxidant activity stimulator for aquaculture species. Besides, soybean lecithin is also reported to help aquaculture species being resilient to physical and chemical stressors. In this review, common sources, chemical structure and mode of action of lecithin, with highlight on soybean lecithin application in aquaculture over four-decadal studies published between 1983 and 2023, were evaluated and summarized. By far, soybean lecithin is best-known for its beneficial effects, availability yet cost-effective for aquafeed formulation. Findings from this review also demonstrate that although nutritional profile of long-chain polyunsaturated fatty acids and phosphatidylcholine from egg yolk and marine sources are superior to those from plant sources such as soybean, it is rather costly for sustainable application in aquafeed formulation. Moreover, commercially available products that incorporate soybean lecithin with other feed additives are promising to boost aquaculture production. Overall, effects of soybean lecithin supplementation are well-recognized on larval and juvenile of aquaculture species which having limited ability to biosynthesis phospholipids de novo, and correspondingly attribute to phospholipid, a primary component of soybean lecithin, that is essential for rapid growth during early stages development. In addition, soybean lecithin supplementation plays a distinguish role in stimulating maturation of gonadal development in the adults, especially for crustaceans.
Insects such as black soldier fly larvae (BSFL) are gaining interest among researchers and the aquafeed industry due to the fluctuating price and supply of fish meal (FM). This study evaluated the growth performance, feed stability, blood biochemistry, and liver and gut morphology of Betta splendens using BSFL as an alternative to FM. Five formulated diets were prepared: 0% BSFL, 6.5% BSFL, 13% BSFL, 19.5% BSFL, and 24.5% BSFL. The expansion rate, pellet durability index, floatability, bulk density, and water stability of the prepared feed have been assessed. Except for the diameter of the feed, all the parameters studied differed significantly (p < 0.05) across the experimental diets. After 60 days, the fish fed with 13% BSFL had the highest final length, final weight, net weight gain, specific growth rate, weight gain, and gastrointestinal weight, with mean and standard deviation values of 3.97 ± 0.43 cm, 3.95 ± 0.1 g, 2.78 ± 0.1 g, 4.63 ± 0.17, 4.65 ± 0.13, 237.26 ± 7.9%, and 0.04 ± 0.01 mg, respectively. Similar blood haematology and biochemical properties, including corpuscular volume, lymphocytes, white blood cells, red blood cells, haematocrit, albumin, and alkaline phosphatase, were the highest (p < 0.05) in the 13% BSFL diet group compared to the other treatment groups. In addition, BSFL had a significant impact (p < 0.05) on villus length, width, and crypt depth for the anterior and posterior guts of B. splendens. The 13% BSFL diet group had an intact epithelial barrier in the goblet cell arrangement and a well-organized villus structure and tunica muscularis, compared to the other treatment groups. Furthermore, the liver cell was altered with different BSFL inclusions; the 13% FM group demonstrated better nuclei and cytoplasm structure than the other treatment groups. In conclusion, replacing 13% FM with BSFL could improve the growth performance, blood parameters, and liver and intestine morphology of B. splendens, thus providing a promising alternative diet for ornamental freshwater fish.