Replacing fish oil and astaxanthin by microalgal sources produced different metabolic responses in juvenile rainbow trout fed two types of practical diets

Dietary fish oil supplementation provides n-3 long-chained polyunsaturated fatty acids for supporting fish growth and metabolism and enriching fillet with eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; c22:6n-3). Two experiments were performed as a 3 X 2 factorial arrangement of dietary treatments for 16 weeks to determine effects and mechanisms of replacing 0, 50%, and 100% fish oil with DHA-rich microalgae in combination with synthetic vs microalgal source of astaxanthin in plant protein meal (PM)- or fishmeal (FM)- based diets for juvenile rainbow trout (Oncorhynchus mykiss). Fish (22 ± 0.26 g) were stocked at 17/tank and 3 tanks/diet. The 100% fish oil replacement impaired (P < 0.0001) growth performance, dietary protein and energy utilization, body indices, and tissue accumulation of DHA and EPA in both diet series. The impairments were associated (P < 0.05) with up-regulation of hepatic gene expression related to growth (ghr1and igf1) and biosynthesis of DHA and EPA (fads6 and evol5) that was more dramatic in the FM than PM diet-fed fish, and more pronounced on tissue EPA than DHA concentrations. The source of astaxanthin exerted interaction effects with the fish oil replacement on several measures including muscle total cholesterol concentrations. In conclusion, replacing fish oil by the DHA-rich microalgae produced more negative metabolic responses than the substitution of synthetic astaxanthin by the microalgal source in juvenile rainbow trout fed two types of practical diets.

Protein and Energy Utilization of Black Soldier Fly Maggot at Different age on Chicken

This study aims to determine the efficient use of protein and energy of Black Soldier fly larvae at different age levels on chicken. This research was conducted at Jl. RK, Desa Namo Bitang, Kecamatan Pancur Batu Kabupaten Deli Serdang, North Sumatra. Animal Husbandary Study Program, Faculty of Agriculture, Universitas Sumatra Utara, Medan. The design of this study was a completely randomized design (CRD) with 4 treatments and 5 replications. The treatment consisted of P0, P1, P2, and P3 (larvae 14, 21, 28, and 35 days old). Observed variables were protein digestibility, nitrogen retention and apparent metabolizable energy.The results showed that the treatment had a significant effect (P<0,01) on protein digestibility, nitrogen retention and apparent metabolizable energy. Based on research result it can be concluded that maggot of Black soldier fly more efficient at the age between 24-25 days.

Effects of Mannan Oligosaccharides on Gas Emission, Protein and Energy Utilization, and Fasting Metabolism in Sheep

This study investigated the effects of mannan oligosaccharides (MOS) on in vitro and in vivo gas emission, utilization of crude protein (CP) and energy, and relative parameters of sheep under fasting metabolism conditions. In vitro gas productions were evaluated over 12 h in sheep diets containing different amounts of MOS (from 0% to 6.0%/kg, the increment was 0.5%). A control experiment was used to assess the gas emission, utilization of CP and energy, and fasting metabolism in control sheep and sheep treated with 2.0% MOS over 24 days (d). The results showed that 2.0% MOS supplementation led to the lowest in vitro CO2 production and less CH4 production, while also leading to decrease in vivo nutrients intake, CP and energy excretion, digested and retained CP, and energy released as CH4 (p < 0.05). Furthermore, 2.0% MOS supplementation appeared to decrease in vivo O2 consumption and CH4 production per metabolic body weight (BW0.75), and increase the CP retention rate of sheep (p < 0.074). MOS did not affect other parameters, along with the same parameters of sheep under fasting metabolism conditions (p > 0.05). The findings indicate MOS has only slight effects on the gas emission and nutrients and energy metabolism of sheep.