effects of different stocking densities and diets on the growth and survival rate of black apple snail (pila polita)

CAN THO UNIVERSITY COLLEGE OF AQUACULTURE AND FISHERIES EFFECTS OF DIFFERENT STOCKING DENSITIES AND DIETS ON THE GROWTH AND SURVIVAL RATE OF BLACK APPLE SNAIL (Pila polita) By DANG MINH QUAN A thesis submitted in partial fulfillment of the requirements for the degree of Bachelor of Aquaculture Science Can Tho, December 2013 CAN THO UNIVERSITY COLLEGE OF AQUACULTURE AND FISHERIES EFFECTS OF DIFFERENT STOCKING DENSITIES AND DIETS ON THE GROWTH AND SURVIVAL RATE OF BLACK APPLE SNAIL (Pila polita) By DANG MINH QUAN A thesis submitted in partial fulfillment of the requirements for the degree of Bachelor of Aquaculture Science Supervisor Assoc.Prof.Dr. NGO THI THU THAO Can Tho, December 2013 Acknowledgements First of all, I wish to give my honest thank to Rectorate Board of Can Tho University, lecturers and instructors of CAF and Auburn University who have facilitated for my studying during 4.5 years in Can Tho city. I would like to thank Assoc. Prof. Dr. Ngo Thi Thu Thao and Mr. Le Van Binh who have instructed me enthusiastically to finish this graduating thesis. For other valuable help and guide, thanks are extended to all my friends, Mr. Le Van Binh, Mr. Nguyen Chi, Ms. Nguyen Kim Cuong, Ms. Tran Thi Be Gam, Ms. Nguyen Khanh Linh and friends in AAP course 35. I wish to express my sincere gratitude to my advisor, Dr. Duong Thuy Yen for her constant guidance, and thanks to all my beloved classmates in Advanced Aquaculture Program class for all great encouragement and kind help during 4.5 years in CAF. Finally, I thank my family and all my friends who have supported and encouraged me to study and finish my course. DANG MINH QUAN i ABSTRACT This study consists of two experiments on Black apple snail Pila polita . The first experiment was aimed to evaluate the effects of different densities on the growth and survival rate. There were replicates in each treatment and densities as follow: 300, 600, 900, 1200 ind./m2. Snails with initial weight (0.03g) and shell height (4.5 mm) were reared in the composite tanks and fed with industrial pellet. After 42 days, the survival rate at 300 ind./m2 (94.00%) was higher than at 600 ind./m2 (89.44%), 900 ind./m2 (82.30%) and 1200 ind./m2 (80.89%), there was significant difference (P[...]... Objectives of the study To find out the appropriate foods and stocking density for rearing Black apple snails These results could contribute to improve culture technique of Pila polita 1.3 Contents of research Experiment 1: evaluate the effect of different stocking densities on the growth and survival rate of Black apple snails Experiment 2: evaluate the effect of different diets on the growth and survival rate. .. that feeds and densities significantly affected the growth and survival rates of the snails Vegetables combined with homemade diets resulted in higher growth performance, survival rate and economic efficiency Moreover, stocking with density of 100 snails/m2 showed higher growth, survival rate and economic efficiency than stocking of 150 snails/m2 Nguyen Thi Binh (2011) studied on reproductive and biology... studied the distribution of snails Pila polita, the authors identified Pila polita commonly distributed in Indonesia, China, Thailand and Vietnam The author also reported that Pila polita lived in the farm ponds and midland plains Keawjam (1986) and Thaewnon-ngiw et al (2003) studied on medical effects of Pila polita The authors mentioned that the snail is one of eight species of freshwater snails which... 1986) 2.2.3 Food and nutrition Black apple snail are not selective feeding and eat almost everything available in their environment In general, they prefer soft and digestible vegetation Tougher plants and algae are consumed as long as they are able to grasp pieces of with their radula (rasp tongue) When there is not enough food available in the water, Black apple snails can profit from their amphibian... front part of the foot The middle part and the tail of the foot, the snail remain attached to the side or an object near the surface Once the funnel is filled, the snail brings its head in the funnel and eats the collected material Behaviour is known as ciliary feeding Black apple snails are opportinustic and even consume all kinds of dead animals like dead fish, frogs, crustaceans and insects and eggs... community in southern Thailand 2.4.2 Domestic research activities Nguyen Thi Dat (2010) studied on the effects of different densities and feeds on the growth and survival rate of the snail Pila polita in grow-out period Snails were fed with cassava leaves, homemade feed (40% rice bran, 20% corn, 10% lighter fish meal and 30% soybean meal) Stocking density was 100 snails/m2 and 150 snails/m2 Results... stocking snails in the muddy bottom would be better than others and the survival rate varied from 88.15 to 90.93% after 28 days of cultured 7 period Le Van Binh et al (2013) investigated the effects of different foods on the growth and survival rate of Pila polita The results showed that after 35 days of nursing period, the survival rate of snails in rice bran diet (94.4%) was no significant difference... conducted the study on mangrove snail (Certithidea obtusa) with FCR varied from 20.3 – 46.9 in 3 rearing months Results from FCR in this study indicated that black apple snails in young stage showed effectively uptake and digest food for their growth Table 4 4 Survival rate, biomass growth rate, Feed conversion ratio (FCR) in different stocking densities Parameters Survival rate (%) Biomass growth rate. .. operculum fold on the back side Snails usually float to the surface to breathe, when there is noise, snails immediately withdraw into the shell and drive to the bottom In hot or cold weather, they float to the surface Snails have both gills and lungs so they can live in water and on land Being as fresh water snail, but some Ampullariids species may be able to tolerate at low levels of salinity (Prashad,... at the bottom of the tank then transfer into Falcon tubes (around 50 ml for each tank) and stored in cool condition if needed Microbiological analysis were conducted at the same day This technique was applied only for the second experiment Method of determining the density of bacteria 1 Prepare serial dilutions of the broth culture as shown in the figure from a previous lab exercise (Isolation of Pure . 4. 1.1 Water quality parameters 18 4. 1.2 Growth of Black apple snail 21 4. 1.3 Growth rates of snails 23 4. 1 .4. Biomass growth rate and feed efficiency of snail 24 4. 2. Effects of different diets. period 21 Table 4. 2 The specific growth rate in shell length during experiment (%/day) 23 Table 4. 3 The specific growth rate in snail body weight (SGR weight , %/day) 24 Table 4. 4 Survival rate,. Figure 4. 2 Variation of pH during experimental period 19 Figure 4. 3 Variation of TAN during the culture period 20 Figure 4. 4 Variation of NO 2 during the culture period 20 Figure 4. 5 Variation