LIRONG YU ABIT
Aquarium Advice Newbie
The effects of total and partial replacement of the Brine shrimp Artemia spp. with formulated diet on larval survival and production of Macrobrachium rosenbergii post larvae.
by Lirong Yu Abit and Che Roos Saad
Introduction
Current farming practices used in the culture of the giant freshwater prawn Macrobrachium rosenbergii began in the early 1970’s following the development of hatchery techniques by Ling and Merican (1961) and successful larvae rearing techniques by Fujimura (1966) and Ling (1969). Nonetheless it should be noted that in coastal areas in the Indo-Pacific region, Macrobrachium rosenbergii has been sustaining local fisheries for hundreds of years. (Holthus, 1980). Of the more than 100 known species of Macrobrachium, only Macrobrachium rosenbergii has been commonly used in commercial farming worldwide (New, 1995). This is mainly due to its many favorable characteristics namely good demand and price, large size, relatively fast growth, temperature and disease tolerance as well as ease of obtaining berried females. (Das, 1995). Analysis of past years prawn production in Malaysia has revealed and increasing trend in freshwater prawn production from 1984 to 1996, however the large scale production of Macrobrachium rosenbergii has yet to be refined in terms of seed production and appropriate culture technology. (Roustaian, 1999) One of the major bottlenecks (especially in developing nations) inhibiting the expansion and development of this industry is the over dependence on the brine shrimp (Artemia salina) as an indispensable food. (Lovett and Felder, 1988, Alam et. al., 1993) The main disadvantage of an Artemia based diet is it’s high cost, which may contribute up to 60% of the total production cost. (Hagood and Willis, 1976). Variations in hatchabilty and nutritional value of Artemia from different sources also effects hatchery production. Thus the quest for an easily available, relatively cheap and nutritionally sound diet is desired to reduce the dependency on Artemia in larval rearing operations of Macrobrachium rosenbergii. (Roustaian, 1999) The planktonic development of Macrobrachium rosenbergii encompasses a sequence of eleven moults and intermoult stages during which the feeding regime appears to be the determinant of successful rearing. (Daniels et. al., 1992). Thus far there has been no information on the weaning from Artemia to an artificial diet in larval rearing of Macrobrachium rosenbergii other than Deru (1990). (Raustaian, 1999) Thus the aim of this study is to examine the effects of total and partial replacement of Artemia with formulated diet on larval survival and production of Macrobrachium rosenbergii post larvae.
Materials and Methods
Larvae for stocking were obtained from egg carrying female Macrobrachium rosenbergii (orange egg mass) collected from the Universiti Putra Malaysia Hatchery Complex broodstock. The prawns were disinfected before being placed into 0.25-ton capacity fiberglass hatching tanks containing water of 12-ppt salinity without acclimatization and with mild aeration. After 7-15 days hatching occurred. The newly hatched larvae are phototrophic (Sandifer and Smith, 1985) and were concentrated using a strong lantern before being removed to 10-liter pail by siphoning. The hatching rate of each individual hatching was volumetrically estimated before larvae were stocked into circular fiberglass tanks (inner diameter: 90cm, height: 60cm) containing 100 liters of 12- ppt water. Larvae were stocked at a rate of 5 pieces per liter (5,000 pieces per rearing tank). Larvae were reared with a modified static green water technique (Cheah and Ang, 1979). The salinity of the culture media was gradually lowered by 1 ppt every 3 days by replacement of culture media with fresh water until it reached 6-ppt whereby the salinity was maintained at a constant. Temperature and dissolved oxygen were monitored daily. The experiment had 4 treatments and each treatment was replicated in a Completely Randomized Design. Survival was estimated every 5 days by 3 samplings at different locations in the experimental tanks using 200ml glass beakers. The treatments for the experiment are presented in Table 1.
Table 1: Feeding treatments for Macrobrachium rosenbergii larvae
Treatment Feed Type % of Ration
1) Control Artemia 100
2) CL1 Artemia + Formulated Feed 70: 30
3) CL2 Artemia + Formulated Feed 30: 70
4) CL3 Formulated Feed 100
Artemia were hatched daily and the nauplii were fed at a rate of 3 piece per ml. Feeding was carried out twice a day once in the morning and once in the evening at an ad-libitum rate.
Results and Discussion
The pilot Post Larvae (PL) was observed on the 17th day of culture. Water temperature was stable at 28- 30°C and dissolved oxygen was constantly above 6.5mg/l. The experiment was terminated at day 35, the production of Macrobrachium rosenbergii larvae using various feeding schemes are presented in Table 2.
Table 2: Production of Macrobrachium rosenbergii Post larvae from various feeding treatments
Feeding Treatment Total Post Larvae Production (%) Post Larvae Production (Pieces) Total Survival (%)
1) Control 44.90±1.86 2245±93 53.16±0.13
2) CL1 72.65±7.57 3632.5±378.5 73.05±7.55**
3) CL2 40.04±2.02 2002±101 43.85±1.91
4) CL3 5.03±0.03 251.5±1.5 8.58±0.28
** Highly significant
The findings showed that the treatment CL1 gave the best results in terms of post larvae production and total survival when compared to the other feeding treatments. Moreover the results showed that treatment CL1 surpassed the results of the Control using Artemia. Feeding of Artemia together with an artificial diet at a ratio of 70 Artemia: 30 artificial diet showed significantly better results than when compared to the other feeding treatments in terms of post larvae production and total survival. Poor survival and production of post larvae in the treatment fed solely artificial diet may be explained by the difficulty of the larvae especially in the early stages in capturing the artificial diet, this is probably also the reason that treatment CL2 did not perform as well as the control and CL1 as the ratio of artificial food to Artemia was too high. Roustaian (1999) reported that early planktonic larvae of M. rosenbergii were unable to grasp the food particles of an artificial diet efficiently, however by the time they reached stage V and above they had developed the ability to grasp the food particles. Kamarudin et. al (1994) also reported that early stage larvae of M. rosenbergii have an undeveloped digestive system making it difficult to digest an artificial diet at these early stages. The inferior result of the control when compared to the feeding treatment CL1 may be caused by the difficulty of later stage larvae in capturing smaller Artemia at later stages of growth. Thus it can be concluded that a satisfactory performance in production of Macrobrachium rosenbergii post larvae could be achieved by employing a diet consisting of a mixture of artificial diet and live feed (Artemia) at a ratio of 70 Artemia: 30 artificial diet. However from an economical viewpoint the feeding treatment CL2 would be the most cost effective in terms of larvae survival as compared to feed cost.
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by Lirong Yu Abit and Che Roos Saad
Introduction
Current farming practices used in the culture of the giant freshwater prawn Macrobrachium rosenbergii began in the early 1970’s following the development of hatchery techniques by Ling and Merican (1961) and successful larvae rearing techniques by Fujimura (1966) and Ling (1969). Nonetheless it should be noted that in coastal areas in the Indo-Pacific region, Macrobrachium rosenbergii has been sustaining local fisheries for hundreds of years. (Holthus, 1980). Of the more than 100 known species of Macrobrachium, only Macrobrachium rosenbergii has been commonly used in commercial farming worldwide (New, 1995). This is mainly due to its many favorable characteristics namely good demand and price, large size, relatively fast growth, temperature and disease tolerance as well as ease of obtaining berried females. (Das, 1995). Analysis of past years prawn production in Malaysia has revealed and increasing trend in freshwater prawn production from 1984 to 1996, however the large scale production of Macrobrachium rosenbergii has yet to be refined in terms of seed production and appropriate culture technology. (Roustaian, 1999) One of the major bottlenecks (especially in developing nations) inhibiting the expansion and development of this industry is the over dependence on the brine shrimp (Artemia salina) as an indispensable food. (Lovett and Felder, 1988, Alam et. al., 1993) The main disadvantage of an Artemia based diet is it’s high cost, which may contribute up to 60% of the total production cost. (Hagood and Willis, 1976). Variations in hatchabilty and nutritional value of Artemia from different sources also effects hatchery production. Thus the quest for an easily available, relatively cheap and nutritionally sound diet is desired to reduce the dependency on Artemia in larval rearing operations of Macrobrachium rosenbergii. (Roustaian, 1999) The planktonic development of Macrobrachium rosenbergii encompasses a sequence of eleven moults and intermoult stages during which the feeding regime appears to be the determinant of successful rearing. (Daniels et. al., 1992). Thus far there has been no information on the weaning from Artemia to an artificial diet in larval rearing of Macrobrachium rosenbergii other than Deru (1990). (Raustaian, 1999) Thus the aim of this study is to examine the effects of total and partial replacement of Artemia with formulated diet on larval survival and production of Macrobrachium rosenbergii post larvae.
Materials and Methods
Larvae for stocking were obtained from egg carrying female Macrobrachium rosenbergii (orange egg mass) collected from the Universiti Putra Malaysia Hatchery Complex broodstock. The prawns were disinfected before being placed into 0.25-ton capacity fiberglass hatching tanks containing water of 12-ppt salinity without acclimatization and with mild aeration. After 7-15 days hatching occurred. The newly hatched larvae are phototrophic (Sandifer and Smith, 1985) and were concentrated using a strong lantern before being removed to 10-liter pail by siphoning. The hatching rate of each individual hatching was volumetrically estimated before larvae were stocked into circular fiberglass tanks (inner diameter: 90cm, height: 60cm) containing 100 liters of 12- ppt water. Larvae were stocked at a rate of 5 pieces per liter (5,000 pieces per rearing tank). Larvae were reared with a modified static green water technique (Cheah and Ang, 1979). The salinity of the culture media was gradually lowered by 1 ppt every 3 days by replacement of culture media with fresh water until it reached 6-ppt whereby the salinity was maintained at a constant. Temperature and dissolved oxygen were monitored daily. The experiment had 4 treatments and each treatment was replicated in a Completely Randomized Design. Survival was estimated every 5 days by 3 samplings at different locations in the experimental tanks using 200ml glass beakers. The treatments for the experiment are presented in Table 1.
Table 1: Feeding treatments for Macrobrachium rosenbergii larvae
Treatment Feed Type % of Ration
1) Control Artemia 100
2) CL1 Artemia + Formulated Feed 70: 30
3) CL2 Artemia + Formulated Feed 30: 70
4) CL3 Formulated Feed 100
Artemia were hatched daily and the nauplii were fed at a rate of 3 piece per ml. Feeding was carried out twice a day once in the morning and once in the evening at an ad-libitum rate.
Results and Discussion
The pilot Post Larvae (PL) was observed on the 17th day of culture. Water temperature was stable at 28- 30°C and dissolved oxygen was constantly above 6.5mg/l. The experiment was terminated at day 35, the production of Macrobrachium rosenbergii larvae using various feeding schemes are presented in Table 2.
Table 2: Production of Macrobrachium rosenbergii Post larvae from various feeding treatments
Feeding Treatment Total Post Larvae Production (%) Post Larvae Production (Pieces) Total Survival (%)
1) Control 44.90±1.86 2245±93 53.16±0.13
2) CL1 72.65±7.57 3632.5±378.5 73.05±7.55**
3) CL2 40.04±2.02 2002±101 43.85±1.91
4) CL3 5.03±0.03 251.5±1.5 8.58±0.28
** Highly significant
The findings showed that the treatment CL1 gave the best results in terms of post larvae production and total survival when compared to the other feeding treatments. Moreover the results showed that treatment CL1 surpassed the results of the Control using Artemia. Feeding of Artemia together with an artificial diet at a ratio of 70 Artemia: 30 artificial diet showed significantly better results than when compared to the other feeding treatments in terms of post larvae production and total survival. Poor survival and production of post larvae in the treatment fed solely artificial diet may be explained by the difficulty of the larvae especially in the early stages in capturing the artificial diet, this is probably also the reason that treatment CL2 did not perform as well as the control and CL1 as the ratio of artificial food to Artemia was too high. Roustaian (1999) reported that early planktonic larvae of M. rosenbergii were unable to grasp the food particles of an artificial diet efficiently, however by the time they reached stage V and above they had developed the ability to grasp the food particles. Kamarudin et. al (1994) also reported that early stage larvae of M. rosenbergii have an undeveloped digestive system making it difficult to digest an artificial diet at these early stages. The inferior result of the control when compared to the feeding treatment CL1 may be caused by the difficulty of later stage larvae in capturing smaller Artemia at later stages of growth. Thus it can be concluded that a satisfactory performance in production of Macrobrachium rosenbergii post larvae could be achieved by employing a diet consisting of a mixture of artificial diet and live feed (Artemia) at a ratio of 70 Artemia: 30 artificial diet. However from an economical viewpoint the feeding treatment CL2 would be the most cost effective in terms of larvae survival as compared to feed cost.
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