SELECTION OF HOST DERIVED PROBIOTICS FOR GROWTH IMPROVEMENT OF HYBRID GROUPER (Epinephelus spp.)

Ain Zulkurnain¹, Ahmad Daud Om², Noordiyana Mat Noordin¹, Shumpei Iehata^1*

¹Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, 21300 Kuala Nerus, Terengganu, Malaysia

²Fisheries Research Institute Tanjung Demong, 22200 Besut, Terengganu, Malaysia

*Corresponding author: shumpei@umt.edu.my

Hybrid grouper (Epinephelus spp.) is a commercially important aquaculture species in Southeast Asia including Malaysia. However, the escalating amount of hybrid grouper culture may risk various exposure to various new infectious disease caused by viruses, parasites, bacteria, fungi and other pathogens. Probiotics has been introduced as a suitable alternative to antibiotics as the demand for eco-friendly farming has increased and their reported benefit to the host by enhancing feed utilisation and immune response. This study aimed to test the effects of varying concentrations of indigenous bacteria isolated from the gut of hybrid grouper as probiotics on the growth performance of juvenile hybrid grouper. The potential candidates were identified preliminary by gram staining test and catalase test and then the candidates were subjected to antagonistic test and quantification of enzymatic activity test. The antagonistic effects of the probiotic candidates were determined against Vibrio algynolyticus and Aeromonas hydrophila using double layer assay method. For enzymatic activity test, the probiotic candidates were tested for proteolytic, cellulolytic and lipolytic activity respectively. Selected candidates were then identified through 16S rRNA gene sequencing. Out of forty-four potential probiotic candidates, strain A8 showed significantly higher antagonistic and enzymatic activity, and identified as Bacillus sp. Thereafter, Bacillus sp. (strain A8) with different concentrations were supplemented along the diet in an 8-week feeding trial of juvenile hybrid groupers. One thousand juvenile hybrid groupers were randomly allotted to 20 aquariums (5 replicates per treatment) and fed to apparent satiation twice a day. The sampling results for a 2-week feeding trial period showed higher weight gain in the probiotic with high concentration. According to these results, the diet supplemented with high concentration of probiotic is good for the growth of juvenile hybrid grouper.

Keywords: Bacillus sp., Epinephelus spp., probiotics, hybrid grouper

MOULTING STAGES IN MUD CRAB GENUS Scylla.

Azmie, G¹., Ikhwanuddin, M.¹, Fazhan, H¹., Waiho, K.¹

¹Higher Institution Center of Excellence, Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, Terengganu, Malaysia

^*Corresponding author: azmie@umt.edu.my

Crustaceans such as shrimps and crabs are encased in a rigid and hard exoskeleton, which periodically shed off to grow. The shedding off the old exoskeleton are generally referred as the moulting process and considered as one of the important yet risky process in crustaceans. The duration of the moulting process is species dependent and few morphological changes occurred and can be observed macroscopically and microscopically. These morphological changes and the duration of the moulting process are among the indicator used in determining the moulting stages in crustaceans, such as crabs. Although mud crab genus Scylla are among the important species in aquaculture sector in Southeast Asian, including Malaysia, their moulting process and the characterization of moulting stages, however, is limited and scarce and not well elaborated.  A simple and practical methods for the identification of moulting stages in mud crab is useful for the expansion of the mud crab aquaculture. Therefore, this study was design to identify and characterize the moulting stages in mud crab genus Scylla. Moulting stages of mud crab were classified into four stages which are Intermoult, Premoult, Ecdysis and Postmoult.

Keywords: Crustacean, Mud crab, Scylla, Moulting, Aquaculture

EFFECT OF SINGLE CELL PROTEIN BIOMASS OF SPIRULINA AS FEED ADDITIVE ON THE GROWTH, SURVIVAL AND FOOD CONVERSION

RATIO OF NILE TILAPIA (Oreochomis niloticus) ISRAEL

STRAIN FRY

Sotero M. Aban^1*, Alvin F. Bruan¹, Maria Elena T. Caguioa²

¹Pangasinan State University-Binmaley Campus, Binmaley, Pangasinan, Philippines

²Tarlac Agricultural University, Camiling Tarlac, Philippines

^*Corresponding author: abansotero1@gmail.com

This study was conducted to evaluate the growth performance, food conversion ratio and survival of Nile Tilapia fingerlings fed diets containing Spirulina. Specifically, the study aims to: (1) evaluate the growth performance of Nile Tilapia fry fed diets with Spirulina in terms of weight gain, length gain, specific growth rate and daily growth rate; (2) determine the food conversion ratio of Nile tilapia fry fed diets with Spirulina; and (3) compare the survival rate of Nile tilapia fry fed diets with and without Spirulina. The  experimental research design used four treatments, namely: Treatment I – 75% Rice Bran + 25% Sarotherodon Fish Meal; Treatment II – 75% Rice Bran + 12.5% Sarotheron Fish Meal + 12.5 Spirulina Meal; Treatment III – 75% Rice Bran + 25% Spirulina Meal; and Treatment IV – Commercial Feed. Each treatment was replicated three times. The 60 days feeding was conducted in 12 culture tanks provided with aeration. Each culture tank was stocked with 20 fry and were fed at 20% of fish biomass for the first month and at 10% of fish biomass for the second month of culture period. The result of the study showed no significant differences (p>0.05) among four treatments in terms of  mean weight gain, mean length gain, specific growth rate and daily growth rate. This result means that the growth of Nile tilapia fry fed with diet containing 12.5% and 25% Spirulina is comparable with those fed with commercial feed and with diet containing 25% Sarotherodon Fish Meal. No significant differences was also observed among four treatments in terms of Food Conversion Ratio and percentage survival rate. Further, the study showed that Spirulina is a good source of protein in the diet of Nile tilapia fry and can replace fish meal from 12.5% to 25%.

Keywords:   Spirulina meal, Nile tilapia fry, Sarotherodon fishmeal

EFFECT OF DIFFERENT PROTEIN LEVELS ON THE GROWTH PERFORMANCE AND SURVIVAL RATE OF TIRE TRACK EEL (Mastacembelus favus) FINGERLING

Nguyen Huu Yen Nhi¹*, Tran Kim Ngoc¹, Trinh Thi Lan¹, Nguyen Thi Thuy Hang¹, Nguyen Thi Bich Hanh¹, Dang Van Ty², Torbjörn Lundh³ and Anders Kiessling³

¹An Giang University, Vietnam National University Ho Chi Minh City, Viet Nam
²Mekong Aquafeed Company Limited, Phu Cuong, Tam Nong, Dong Thap, Viet Nam

³Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden

^*Corresponding author: nhynhi@agu.edu.vn

Tire track eel Mastacembus favus is an important candidate species for commercial aquaculture in Vietnam, therefore, a ninety day-feeding experiment was carried out to determine appropriate protein levels for efficiently rearing tire track eel fingerlings to complete the procedure of raising this species by using commercial feed. The fish were fed one of seven diets formulated with different levels of protein (24%, 29%, 34%, 39%, 44%, 49% and 54%) at the same energy and fat levels. Triplicate groups of 50 tire track eel fingerlings were randomly assigned to 21 identical conical 500-L tanks equipped with an aeration system and substrates for shelter. Feed intake (FI), protein intake (PI), daily weight gain (DWG), specific growth rate (SGR), feed conversion ratio (FCR), feed conversion efficiency (FCE), protein efficiency (PE), survival rate (SR), net protein utilisation (NPU) were determined at the end of the experiment. The highest growth rate of fish fed different levels of protein was obtained in group fish fed 44% protein. DWG of this group (0.093 g/day) was higher than those of the groups (24%, 29%, 34% and 54%, p < 0.05), but there was not different from the remaining groups (39% and 49%, p > 0.05). SGR of fish in group fed the 44% protein (1.59%/day) was similar to those of the groups (39% - 54%) but was higher than the remaining groups (24% - 34%). After ninety-day treatment period, SR of tire track eel were relatively high ranging from 76.7% to 84.7% was no difference between treatment groups (p > 0.05). FCR was lowest in the 44% protein treatment group (1.43). This study revealed that 44% protein content stimulated the best growth and the lowest FCR.

Keywords: protein requirement, tire track eels, optimum growth, Mastacembelus

EVALUATION OF LACTIC AND FORMIC ACIDS IN SILAGE PRODUCTION FROM VISCERA OF GOLDEN REDFISH (Sebastes norvegicus, Ascanius, 1772)

Aysha Akhtar^1,2*, Sigurjon Arason³, Marvin Ingi Einarsson³, Mamun Abdullah Al⁴, SM Sharifuzzaman¹_, Alkassoumi Hassane Hamadou⁵, Abu Hena Mustafa Kamal⁶

¹ Institute of Marine Sciences, University of Chittagong, Chattogram 4331, Bangladesh

² United Nations University, Fisheries Training Programme, Fornubúðir 5220, Hafnarfjörður, Iceland

³Matis, Vínlandsleið 12113, Reykjavík, Iceland

⁴Aquatic Eco-Health Group (AEHG), Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen 361021, China

⁵Jiangnan University, No 1800, Lihu Road, Wuxi, 214122 Jiangsu, China

⁶Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia

*Corresponding author: aysha_imsfcu@yahoo.com

Organic acids either single or in combination have been studied worldwide for producing silage from fish processing wastes. Although, formic acid is popularly used as ensiling agent, there is lack of information on the effectiveness of weak organic acids such as lactic acid. From this perspective, we used both lactic and formic acids for producing silage from the viscera of Golden redfish (Sebastes norvegicus, Ascanius, 1772) under ambient temperature (25⁰C) and elevated temperature (45⁰C) conditions. Temperature 45⁰C was used to accelerate the rate of hydrolysis, and on day 5, heat treatment was performed to inactivate the digestive enzymes for the rest of storage. Changes in organoleptic properties, chemical parameters and nutritional quality of the produced silages were assessed. Lactic acid silages were stabilized at pH 4.09 (25⁰C) and 4.12 (45⁰C) while formic acid silages were found to be stable at pH 3.38 (25⁰C) and 3.26 (45⁰C) respectively. There was no sign of putrefaction in the silages during the entire 35 days storage. Aqueous phase was found to increase due to hydrolysis in both lactic and formic acid silages with time and the proportion was more pronounced in silages at 45⁰C. An increase of protein in soluble phase was observed in all the silages as compared to initial stage. However, the protein was proportionately higher in lactic acid silages than their formic acid counterparts. A higher concentration of tryptophan was obtained in both lactic acid and formic acid silages (25 ⁰C) in comparison to untreated raw material. Initially, free fatty acid content rose gradually in the silages before slowing down. The increase was proportionately higher in silages at 45⁰C due probably to influence of higher temperature. Overall, our results suggest that lactic acid could be used as effectively as formic acid to produce silage from fish viscera.  

Keywords: Organic acids, Silage, Formic acid, Lactic acid, Golden redfish, Fish viscera, hydrolysis, Tryptophan, Free fatty acid