1 EFFECTS OF DIFFERENT FEEDING REGIME, WEANING PERIOD AND STOCKING DENSITY ON THE SURVIVAL AND GROWTH OF STINGING CATFISH FRY (Heteropneustes fossilis, Bloch) THEERAWAT SAMPHAWAMANA st

2 CHAPTER 1 INTRODUCTION Distribute in South-Asia and South-east Asia. Good taste High price High nutritive Heteropneustes fossilis, (Bloch) Yadav, 1999

3 Problem statement Major constraints of H. fossilis larvae rearing is the high rate of mortality. How to improve the survival? 1. Feeding regime 2. Weaning period 3. Stocking density

Reported studies Feeding regime Live-feeds are essential for carnivorous fish at the first stage (Dabrowski and Culver, 1991). Weaning period Co-feeding live-feed and artificial diets provided higher growth and survival than feeding either live-feeds or micro-diets alone (Giri et al., 2002). Stocking density Over-stocking has consequently slow growth and low survival (Shepherd and Bromage, 1992).

5 Experimental design Determine the proper stocking density Rearing weaned fry with different stocking densities Select the best weaning procedure Weaning fish fry onto artificial diets with different acclimation schedules Select the best live-feed Experiment 1 Nursing fry with different live-feeds Recommend the suitable nursing protocols Experiment 2 Experiment 3

6 Experiment 1 To evaluate the effect of different live feeds on the growth and survival of H. fossilis fry at the first stage. Null hypothesis: There is no effect of different live feeds on the survival and growth of H. fossilis fry. Experiment period: 21 days 4 treatments and 4 replications. Two days-old fry were reared with 3 different types of live feeds.

7 Design of Experiment 1 Trt FeedSDREP 1A1ARotifer 8 fry/L4 2A2AArtemia 8 fry/L4 3A3AMoina 1 st week: small-size Moina After 1 st week: ungraded Moina 8 fry/L4 4A4A1 st week: Rotifer 2 nd week: Artemia 3 rd week: Moina 8 fry/L4

8 Artemia : mm Small-size Moina : mm Rotifer: mm Ungraded Moina : mm

Live-feeds Rotifer Ungraded Moina Artemia 9

Treatment3:Moina were graded by sieving through 400 micron seine net during the first week. 400 micron 69 micron 10

Fish sample (2 day-old) 11

Maintenance of experiment tanks 12

Length and weight measurement 13

Fish mouth measurement 14

15 Results of experiment 1 Parameters 1A Fed Rotifer 2A Fed Artemia 3A Fed Moina 4A Combination Mean final weight FMW (mg) c ± b ± a ± b ± 21 Daily weight gain DWG (mg/day) 1.27 c ± b ± a ± ab ± 3.0 Specific growth rate SGR (%) c ± b ± a ± ab ± 0.5 Mean final length FML (%) c ± b ± a ± ab ± 7 Survival (%) b ± a ± a ± a ± 3.0 Fry fed Moina showed the best growth

Supporting literature speciesProtein %Fibre %Fat %Ash % Moina Artemia Rotifer Source of data: Watanabe (1994) 16 This might have resulted from the higher nutritive value.

17 Size of fish mouth and live-feeds Type of live-feeds RotiferArtemia Small- size Moina Ungraded -Moina Size (mm) Age of fry2 days7 days 14 days21 days Size (mm) This might have resulted from the appropriate size.

Comparison between size of fry mouth and live-feeds (micron) 18 Appropriate size of live-feeds for larval feeding should be approximately 50% of fish mouth size (Shirota, 1970)

Comparison between size of fry mouth and live-feeds (micron) 19 Fry should be fed with small-size Moina in the first week due to the appropriate size.

Comparison between size of fry mouth and live-feeds (micron) 20 Fry should be fed with small-size Moina in the first week due to the appropriate size.

Comparison between size of fry mouth and live-feeds (micron) 21

Comparison between size of fry mouth and live-feeds (micron) 22

23 Experimental design Determine the proper stocking density Rearing weaned fry with different stocking densities Select the best weaning procedure Weaning fish fry onto artificial diets with different acclimation schedules Select the best live-feed Experiment 1 Nursing fry with different live-feeds Recommend the suitable nursing protocols Experiment 2 Experiment 3 Moina

24 Experiment 2 To investigate the effect of weaning periods in terms of different acclimation schedules weaning onto artificial diets. Null hypothesis: There is no effect of different weaning periods on the survival and growth of H. fossilis fry. 6 treatments and 4 replications Experiment period: 30 days Weaning periods: 0, 5, 10, 15, and 20 days were investigated.

25 Design of experiment 2 Live feed (time/day) Dry feed (time/day) Live control Dry control change every 1 day change every 2 day change every 3 day change every 4 day Total acclimatization weaning period (day) Total experiment duration (day) 30 - : continuous feeding of live feed or dry feed

26 Artificial diets Two types of artificial feeds were used FeedNo.1No.2 Type Particle size Moisture (%) Crude protein (%) Crude Lipid (%) Crude Fibre (%) Ash (%) Powder feed mm Sinking pellet feed 1.0–1.7 mm composition of dry-feeds used in experiments Thailuxe company

Artificial diets 27

Maintenance and measurement 28

29 Results of experiment 2 parameters Live control Dry control change every 1 day change every 2 day change every 3 day change every 4 day Mean final weight (mg) a ± d ± c ± b ± a ± a ± 19 Daily weight gain (mg/day) 5.36 a ± d ± c ± b ± a ± a ± 0.6 Specific growth rate(%) 16.9 a ± d ± c ± b ± a ± a ± 0.4 Mean final length (mm) 28.6 a ± d ± c ± b ± a ± a ± 1.7 Survival (%) a ± d ± c ± b ± a ± a ± 2.3

Discussion H. fossilis fry could not be activated to artificial feed by directly feeding them with dry feed. H. fossilis fry can be weaned from live-feed to artificial feed by introducing dry feed every 3 days intervals (15 days weaning intervals). The selection of 3 days intervals would be economically advantageous as it assist to reduce live-feed requirement. 30

31 Experimental design Determine the proper stocking density Rearing weaned fry with different stocking densities Select the best weaning procedure Weaning fish fry onto artificial diets with different acclimation schedules Moina Experiment 1 Nursing fry with different live-feeds Recommend the suitable nursing protocols Experiment 2 Experiment 3 15 days weaning schedules (change every 3 day)

32 Experiment 3 To determine the optimum rearing density. Null hypothesis: There is no effect of different stocking densities on the survival and growth of H. fossilis fry. Fry were fed with sinking pellet feed No.2 Set up with 5 treatments, 3 replications Experiment period: 60 days

33 Design of experiment 3 Treatment Stocking density ( fry/L) Feedreplication 1C 2C 3C 4C 5C No Dry feed:Thailuxe company

Experiment 3 34

Length and weight measurement 35

36 Results of experiment 3 parameters4 fry/L6 fry/L8 fry/L10 fry/L12 fry/L Mean final weight(mg) 1,238 a ± 31 1,130 a ± 26 1,106 a ± 34 1,088 b ± b ± 33 Daily weight gain(mg/day) a ± b ± c ± c ± c ± 0.3 Specific growth rate(%) 11.8 a ± a ± a ± a ± b ± 0.22 MFL (cm) 6.08 a ± a ± a ± b ± c ± 0.63 Survival (%) 39.6 a ± a ± a ± b ± b ± 2.1

Discussion Optimum stocking density of H. fossilis is 8 fry/L. Over-stocking has negative impact on growth and survival rate due to the competition for space. This might be due to stress. Low temperature might have caused low survival in all treatments. 37

Comparison between water quality parameters during experiment periods and optimum level parametersExperiment 1Experiment 2Experiment 3 optimum level DO > 5 Temp pH TAN < 0.1 NO < 0.1 Source of optimum level data: (Boyd,1990) 38

39 Experimental design Determine the proper stocking density Rearing weaned fry with different stocking densities 15 day weaning schedules Weaning fish fry onto artificial diets with different acclimation schedules Moina Experiment 1 Nursing fry with different live-feeds Recommend the suitable nursing protocols Experiment 2 Experiment 3 8 fry / L

Conclusions Hypothesis 1: Moina is the most suitable live-feed for H. fossilis larval rearing at the first 3 weeks. Hypothesis 2: H. fossilis fry can be completely weaned from Moina to artificial-feeds within 15 days with 3 gradually acclimatization per each live-feed to artificial-feeds combination. Hypothesis 3: 8 fry/L is optimum stocking density of post-weaned H. fossilis fry rearing until achieving the fingerling size (3 month-old). 40

Recommendation Comparison between H. fossilis fed small-size Moina and ungraded Moina at the first week should be done to evaluate the effect of different size, in term of growth and survival. The development of suitable growth-out system for achieving the marketable size should be conducted. During the experiment periods, affected should be paid for maintain optimum environment parameters, such as water temperature. 41

Thank you 42