Effect of protein and lipids levels in a growth diet on adult whitebait Galaxias maculatus (Jenyns 1842)

Galaxias maculatus aquaculture objectives is to produce millions of eggs. Wild females are small (2 g), have quick sexual maturity and low mean fecundity (500 eggs/female), requiring larger fishes with higher fecundity. This study aim is to evaluate experimentally the effect of the levels of protein, lipid and dietary energy on weight increases in adults. Five independent experiments were performed at different sequential time periods at the UCT hatchery, Chile. Specimens were obtained from a) Crystalline sea return specimen catches in the Tolten estuary (4 -6 cm, 0.3-0.4 g.). b) Hatchery cultured fish. Fish were fed by hand ad libitum. In experiments 1 to 4, pelleted diets were prepared with 3 to 5 levels of protein (treatments 27 up to 57%), crumble size, three 100 L fibre ponds replicates. In experiment 5 the effect of two lipid levels (8 and 21%) was evaluated with commercial extruded Salmon Nutra Starter isoproteic crumble 1 diet at 63%, replicated in 4 ponds. The results show: A tendency to increased weight in all sizes with an increased protein level in the pelleted diet.A maximal adult growth is obtained with a diet containing a minimum of 37% crude protein, with 40% the optimal value. A higher % protein in the diet or growth in weight lower feed conversion ratio. The feed conversion ratio in the extruded diet reaches up to 0.5 and in the pelleted vary from 0.7 to 1.5. Fish 0.6 g fed with 63% protein, extruded commercial diet with two different lipid levels (8 and 21%, 20.40 and 23.84 MJ kg-1, PE/TE 0.62 and 0.71) increased weight the first month 67 and 105% each. It has been established that high-energy diets with optimal levels of protein and lipid are a good short-term solution to obtain G. maculatus of higher weight.

Influence of Syzygium cumini extract as feed additives on performance and haematological parameters of commercial broiler chickens

Phytogenies have been widely used as alternative feed additives to replace antibiotics in animal production. The present study aims to evaluate inclusion of S. cumini extract as feed additives on performance and haematological parameters of commercial broiler chickens. A total of 100-day-old commercial chickens (mixed sex) were randomly allocated to four treatments with five replicates. Each treatment was administrated different level of S. cumini extract in the drinking water (P0=control, P1=0.25 g/l drinking water, P2=0.50 g/l drinking water and P3=1.0 g/l drinking water). Commercial diet was provided during experiment based on nutrition requirement for starter and grower. Water and feed were given ad libitum. Data were collected to measure broiler performances and haematological parameters. One way ANOVA was applied in this study and significantly different among treatments were stated (P≥0.05). The results indicated that inclusion of S.cumini extract as feed additives in drinking water did not significantly affected (P>0.05) on animal performances and haematological parameters of commercial broiler chickens. Therefore, it concluded that S.cumini extract can be applied as alternative feed additive due to no negative effects of the S.cumini iextract on performances and haematological parameters.

Growth and survival rate of freshwater lobster (Cherax quadricarinatus) fed different forage feed

Lobster is among freshwater crustaceans which is potentially cultivated in aquaculture system. This present study was conducted to determine the growth and survival rate of freshwater lobster Cherax quadricarinatus fed different forage feed. The experimental methode used a completely randomized design consisted of 4 treatments in triplicate: commercial diet (PL), commercial diet and carrots (PW), commercial diet and potatoes (PK) and commercial diet and sweet potatoes (PU). The experimental lobsters were 5-7 cm in size and 6-8 g in weight. Results indicated that forage feeding can affect the total weight and length, weight gain, specific growth rate and survival rate of lobster. Data showed the best weight gain and specific growth rate were found in PW (34.37±0.30%) and (1.05±0.03%), respectively. The lowest survival rate was seen in PU at 86.67%. However, the best feed conversion ratio gained by PL at 1.74±0.09. This study suggested that the combination of commercial diet with carrots provided the best growth performances in freshwater lobster Cherax quadricarinatus.

Periphyton Technology Enhances Growth Performance and Delays Prolific Breeding of Nile Tilapia, Oreochromis niloticus (Linnaeus, 1758), Juveniles

This study evaluated the effect of periphyton technology (PPT) on the growth performance and breeding schedule of Oreochromis niloticus (Linnaeus, 1758) juveniles. Six ponds, each measuring 81 m2 were used for the study. The ponds were applied with agricultural lime at a rate of 4 g.m-2, and fertilised using chicken manure to facilitate primary productivity. The PPT ponds were fitted with two-metre-long eucalyptus poles of 5 cm diameter placed at 50 cm intervals with the regular addition of molasses as a carbon source. Tilapia juveniles were stocked at a density of 3 fish.m-2 in all ponds and fed on a commercial diet of 20 % crude protein (CP) twice daily at 3 % body weight. Fish were sampled weekly for growth and survival data and bi-weekly for fecundity estimates. The PPT-ponds registered significantly higher survival rate (97.50 ± 0.35 %), mean weight (150.69 ± 0.99 g), specific growth rate (SGR) (2.75 ± 0.01), and feed conversion ratio (FCR) (1.29 ± 0.01), than the control ponds, which registered survival (91.15 ± 0.88 %), mean weight (99.23 ± 0.96 g), SGR (2.29 ± 0.00), and FCR (1.58 ± 0.01). There was significantly higher fecundity in the PPT-ponds (2.28 ± 0.09 g.fish-1) than control (1.74 ± 0.06 g.fish-1), with prolific spawning starting 4 weeks earlier in the control ponds than in the PPT-ponds. This study demonstrated the potential of PPT for enhancing tilapia growth while delaying prolific breeding behaviour. Further studies should explore PPT in replacing synthetic hormones for sex-reversal of tilapia fry in hatcheries.

Utilization of spent millet from locally fermented drink (Burukutu) as experimental diets for Clarias gariepinus

Brewer’s waste is one of the promising carbohydrate and protein source by-products for fish diets. A 10-wk feeding trial experiment involving 10 different diets (10 diets for Spent millet, from locally fermented drink (Burukutu) with increasing levels of brewer’s waste (40% crude protein) was carried out to evaluate the use of spent millet, from Burukutu production in Clarias gariepinus diets in place of normal Corn. Growth performance was compared against a control diet formulated to have similar composition to a typical commercial diet. 10 experimental diets replaced successively 0%, 10%, 20%, 30%, 40%, 50%, 70%, 80%, 90%, and 100% of the Corn carbohydrate with Spent millet from locally fermented drink, Burukutu.. The diets were isonitrogenous and isocaloric. A relatively good growth performance and nutrient utilization by Clarias gariepinus fed the test diets were observed. However, the results showed significant difference (p<0.05) in weight gain, SGR, FCR and RGR between treatments, with the control performing best. The result also showed that survival rate was high in all the treatment which indicate that, spent millet from burukutu production has no adverse effect on the experimented fish. Based on this research, it wasconcluded that 50% of the corn carbohydrate in a typicalcommercial diet could be replaced with spent grain (millet) from locally fermented drink (BKT) withno adverse effect on growth and feed utilization for Clarias gariepinus.

Fatty acid homeostasis in honey bees (Apis mellifera) fed commercial diet supplements

Honey bees obtain lipids from pollen or commercial supplements. These supplements do not fully support colony health. We tested the hypothesis that supplements are deficient because they lack essential fatty acids (EFAs). The five supplements we tested had low linolenic (⍵3) acid and were unbalanced (⍵6:⍵3 > 6) compared to natural pollen. We selected two of these supplements for further study because they had different levels of individual EFAs and different ⍵6:⍵3 ratios. Bees from hives fed these different supplements had equivalent tissue EFA levels. In choice assays, hives fed these different supplements were presented with flours with various absolute and relative levels of EFAs. We saw no difference in foraging preference. Rather, all hives preferred flours with small grain size and high protein to lipid ratios. We conclude that bees balance their internal EFAs and that differential colony nutrition does not affect foraging preference. The data also argue for more linolenic (⍵3) acid in commercial supplements.

Study on Utilization of Black Soldier Fly Larvae (Hermetia illucens) as Protein Substitute in the Pellet Diet of Clarias gariepenus Fingerling

Fish farming faces the challenge of the high cost of feeds because of the cost of high-quality protein like fish meal required in food formulations. Therefore, the need for alternative protein sources is much needed. Black soldier larvae (Hermetia illucens) are alternative feed containing high protein. BSF larvae contain high protein levels (42.7% dry matter; DM). Fish diets should contain 32% to 45% protein content. Therefore, it can be a substitute for a fish meal. This study was conducted to investigate the effect of freshwater fish meal replacement with black soldier fly larvae meal (BSFLM) on the growth rate of Clarias gariepenus fingerling. The effect of freshwater fish meal replacement with black soldier fly larvae (BSFLM) was investigated. This study involved the cultivation of Clarias gariepenus fingerling given BSFLM and a commercial diet. The results showed a difference between the weight gains of C. gariepenus, which were 6.46g in BSFLM, while the commercial diet was 1.9g during 28 days of experiments. There was also no significant difference (p <.05) in the mean weight gain, specific growth rate (SGR), and survival rate. Using BSFLM as an alternative source of protein in fish farming can reduce costs in the aquaculture industry without changing its quality.

Immune Status and Hepatic Antioxidant Capacity of Gilthead Seabream Sparus aurata Juveniles Fed Yeast and Microalga Derived β-glucans

This work aimed to evaluate the effects of dietary supplementation with β-glucans extracted from yeast (Saccharomyces cerevisiae) and microalga (Phaeodactylum tricornutum) on gene expression, oxidative stress biomarkers and plasma immune parameters in gilthead seabream (Sparus aurata) juveniles. A practical commercial diet was used as the control (CTRL), and three others based on CTRL were further supplemented with different β-glucan extracts. One was derived from S. cerevisiae (diet MG) and two different extracts of 21% and 37% P. tricornutum-derived β-glucans (defined as Phaeo21 and Phaeo37), to give a final 0.06% β-glucan dietary concentration. Quadruplicate groups of 95 gilthead seabream (initial body weight: 4.1 ± 0.1 g) were fed to satiation three times a day for 8 weeks in a pulse-feeding regimen, with experimental diets intercalated with the CTRL dietary treatment every 2 weeks. After 8 weeks of feeding, all groups showed equal growth performance and no changes were found in plasma innate immune status. Nonetheless, fish groups fed β-glucans supplemented diets showed an improved anti-oxidant status compared to those fed CTRL at both sampling points (i.e., 2 and 8 weeks). The intestinal gene expression analysis highlighted the immunomodulatory role of Phaeo37 diet after 8 weeks, inducing an immune tolerance effect in gilthead seabream intestine, and a general down-regulation of immune-related gene expression. In conclusion, the results suggest that the dietary pulse administration of a P. tricornutum 37% enriched-β-glucans extract might be used as a counter-measure in a context of gut inflammation, due to its immune-tolerant and anti-oxidative effects.

Diet affects body color and energy metabolism in the Baikal endemic amphipod Eulimnogammarus cyaneus maintained in laboratory conditions

Proper diet is critical for laboratory-reared animals, as it may affect not only their welfare, but also experimental results. Amphipods (Crustacea: Amphipoda) play important roles in ecosystems and are often used in environmental research. Endemic amphipods from the ancient Lake Baikal are promising for laboratory bioassays; however, there are currently no laboratory cultures. In this work, we determine how different diets affect the color and metabolism of a laboratory-reared Baikal amphipod, Eulimnogammarus cyaneus. We found that in freshly collected blue-colored animals, body color correlated with total carotenoid content. Total carotenoid levels did not differ after long-term (two months) feeding with a close to natural carotenoid-enriched, or even a carotenoid-depleted diet. Nevertheless, antennae color was closer to red in the natural-like diet group. It is likely that the carotenoids from the commercial diet are not properly metabolized in E. cyaneus. The animals fed commercial diets had a higher glycogen content, which may signify a higher metabolic rate. Overall, we show that a carotenoid-enriched diet optimized for decapods is not optimal for amphipods, likely due to different carotenoid compositions, and the diet for long-term rearing of E. cyaneus and other Baikal amphipods requires supplementation.

Dried acetes as growth promoter for guppy (Poecilia reticulata) nutrition

Acetes is a marine shrimp that is still an under-studied source as feed ingredient for tropical ornamental fish. Ornamental fish is regarded as pet fish due to its mystic attractiveness for pet fish enthusiasts and requires good protein source to attain good growth and skin colour enhancement. The prevailing feed industry due to continuos pandemic has resulted many enthusiasts to look for alternative growth promoter as feed for guppy. The aims of this study were to determine the nutritional composition in dried Acetes and to investigate the effects of dietary dried Acetes meal on growth performance of Guppy (Poecilia reticulate). Five dietary isocaloric feeds namely Tcontrol (commercial feed only), T0 (100% commercial feed and 0% of dried Acetes.), T1 (75% commercial diet and 25% of dried Acetes spp.), T2 (50% commercial diet and 50% of dried Acetes), T3 (25% commercial diet and 75% of dried Acetes) and T4 (0% commercial diet and 100% of dried Acetes) were formulated as feed for juveniles of Guppy (Poecilia reticulata) reared in triplicates for 30 days. Growth indices like Body Weight Gain, Feed Conversion Rate, Feed Intake and Survival Rate were observed in every 10 days. Results indicated that T4 with 100% dried Acetes attained a significantly high BWG of 222.6% with low feed intake and FCR of less than 3.5. It can be concluded that inclusion of 50 to 100% dried Acetes in feed has contributed to optimal growth performance of guppy. It is also recommended that further studies on dietary Acetes could be done to examine other properties that could be further developed as superfeed for ornamental fish and thereby enhance growth and productivity of the ornamental fish industry as well as economic efficiency.