- Email: [email protected]
Feed utilization, growth and survival of Clarias gariepinus (Burchell 1822) fingerlings cultured under different photoperiods
Aquaculture 283 (2008) 64–67
Contents lists available at ScienceDirect
Aquaculture j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / a q u a - o n l i n e
Feed utilization, growth and survival of Clarias gariepinus (Burchell 1822) fingerlings cultured under different photoperiods Morenike A. Adewolu ⁎, Comfort A. Adeniji, Ademola B. Adejobi Fisheries Dept, Faculty of Science, Lagos State University, P.M.B 00I,LASU Post Office, Badagry Expressway, Ojo, Lagos, Nigeria
a r t i c l e
i n f o
Article history: Received 10 March 2008 Received in revised form 13 July 2008 Accepted 14 July 2008 Keywords: Photoperiods Clarias gariepinus Growth Feed utilization Survival
a b s t r a c t This study assessed the effects of three photoperiods on growth, feed utilization and survival of African catfish, Clarias gariepinus fingerlings. Fish of initial weight 1.15 ± 0.03 g(mean ± SEM) were exposed to 24 h of darkness (DD), 12 h of darkness and 12 h of light (DL) and 24 h of light (LL) for a period of 70 days in a partial flow-through system. The fingerlings were cultured in triplicate groups and fed on 35% crude protein prepared diet at 5% body weight. Fingerlings reared in darkness (DD) had significantly (P b 0.05) highest feed intake, weight gain, protein efficiency ratio, specific growth rate and percentage survival followed by fingerlings cultured in DL which were significantly (P b 0.05) higher than those in LL. Also, the fingerlings cultured in DD had significantly (P b 0.05) lowest uneaten feed and feed conversion ratio, than those reared in DL and LL. There were no significant (P N 0.05) differences in the water temperature and pH of fingerlings cultured under the three different photoperiods, however, dissolved oxygen concentration was significantly (P b 0.05) reduced when the fingerlings were cultured in 24 hour darkness. Fish cultured in DD had darker skin colorations than those in LL. The results of this study show that growth, feed utilization and survival of C. gariepinus fingerlings were improved when cultured in 24 h of darkness. © 2008 Elsevier B.V. All rights reserved.
1. Introduction Photoperiod is known to affect fish feeding activity and play a decisive role in growth and survival (Nwosu and Holzlöhner, 2000). It has the tendency to influence the overall fish performance. Consequently, correct application of photoperiod may improve performance, profitability and sustainability of aquacultural practices. The African catfish (Clarias gariepinus) is one of the most important fish species currently being cultured both within and outside its natural range of tropical and subtropical environments. Its ability to breathe air and withstand poor water quality as well as its high consumer acceptability and tasty flesh makes it of commercial importance (Hecht and Appelbaum, 1988; Van Weerd, 1995; Appelbaum and Kamler, 2000). Britz and Pienaar (1992) reported that restriction of light may be used in its culture to enhance growth and reduce stress, this collaborates the view of Ogbe et al. (2001) who reported that C. gariepinus are bottom feeders that feed comfortably in the dark. These seem to suggest that light plays a major role in regulating the activities of C. gariepinus particularly feeding (Nwosu and Holzlöhner, 2000; Appelbaum and Mcgeer, 1998) and growth. The effect of photoperiod on growth and survival of C. gariepinus at the larval stage has been demonstrated by several authors (Britz and Pienaar, 1992; Appelbaum and Kamler, 2000; Appelbaum and Mcgeer, ⁎ Corresponding author. Tel.: +234 803 056 7600. E-mail address: [email protected] (M.A. Adewolu). 0044-8486/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.aquaculture.2008.07.020
1998; Almazan-Rueda, 2004). However, there is paucity of information on the effect of photoperiod at the fingerling stage; more so that photoperiod is both species and age specific (Boeuf and Bail, 1999). Thus the need to establish the influence of different photoperiods on the performance of C. gariepinus, especially in a rapidly emerging aquaculture industry as obtains in Nigeria. It is against this background that this study was designed to establish the effect of different photoperiods on the growth, feed utilization and survival of C. gariepinus fingerlings. 2. Materials and methods 2.1. Experimental design Three photoperiods: 24 h of darkness (DD), 12 h of darkness and 12 h of light (DL) and 24 h of light (LL) were used as experimental treatments. Triplicate rearing facilities (aquaria) with capacity for 80 L of water and 0.5 m in depth were used for each treatment. Black cellophane polyethylene materials were used to cover off the rearing units to provide 24 h of darkness. The darkened tanks had small holes (3.0 cm) on the cover for food administration as demonstrated by Appelbaum and Mcgeer (1998).The holes were covered immediately after feeding. Normal day was taken as 12 h of light and 12 h of darkness, while rechargeable fluorescent light of 20 W were used to provide light for the remaining 12 h of darkness to give 24 h of continuous light.
M.A. Adewolu et al. / Aquaculture 283 (2008) 64–67
65
Table 1 Percentage composition of prepared feed fed to fingerlings of C. gariepinus reared under different photoperiods
Table 2 Summary of growth and feed utilization of fingerlings cultured under different photoperiods (mean ± SEM)
Ingredients
Percentage incorporation
Parameters
Maize Soybean meal Fish meal Wheat offal Oil Dicalcium phosphate Vitamin/mineral premixa Vitamin C Salt Determined crude protein
33.00 40.00 16.00 7.75 1.00 1.00 0.50 0.50 0.25 35.00
Initial weight/fingerling Weight gain/fish (g) Final weight/fish (g) Specific growth rate Feed consumed/fish (g) Uneaten feed/fish (mg) Feed conversion ratio Protein efficiency ratio Survival percentage
a Each kg of the diet contained 2,000,000 IU vit. A; 4,000,000 IU vit. D3; 200,000 vit. E; 1,200 mg vit. K; 10,000 mg vit. B1; 30,000 mg vit. B2; 19,000 mg vit. B6; 1000 mg vit. B12; 5000 mg Panthotenic acid; 200,000 mg Niacin; 5,000 mg Folic acid; 30 g Mn; 40 g Zn; 40 mg Fe;4 g Cu; 5 g I2; 0.2 mg Co; 600 g calcium; 400 mg choline chloride; 40 mg biotin; 400,000 mg phosphorus; 100,000 mg lysine; 400 g methionine and 125 IU antioxidant.
2.2. Fish management Twenty one (21) day old of C. gariepinus fingerlings of initial weight 1.15 ± 0.03 g (mean ± SEM) and length 4.30 ± 0.20 cm were obtained from the Lagos State University hatchery for the study. The fingerlings were acclimatized for 5 days prior to the start of the experiment and were randomly distributed to nine 80 L aquaria of 0.5 m depth at the stocking rate of 20 fingerlings per aquarium in triplicate, in a partial flow-through system such that daily, there was 50% water exchange to prevent ammonia buildup. The facilities were aerated by means of electric air pumps with air stones throughout the seventy (70) days study period. The fingerlings were fed on a 35% crude protein prepared diet at 5% body weight twice daily at 09.00 h and 18.00 h. The percentage composition of the experimental diet is shown in Table 1. About 30 min after feeding, leftover feed were collected by briefly removing the standpipe at the end of the tank. The outflow was filtered through Whatman filter paper number 1 of 110 mm in diameter. The filtrates (uneaten feed) were air dried, stored and weighed.
Photoperiods DD
DL
LL
± SEM
1.15 1.84a 2.99a 1.37a 3.07a 50c 1.66c 1.73a 93.89a
1.14 1.35b 2.48b 1.12b 2.72b 90b 2.02b 1.42b 88.22b
1.14 0.76c 1.89c 0.86c 2.32c 150a 3.05a 0.94c 81.00c
0.03 0.01 0.01 0.10 0.05 0.05 0.02 0.01 0.01
Mean with the same superscripts in horizontal row are not significantly different (P N 0.05).
2.3.2. Water quality analysis Water temperature in the experimental system was measured daily by using a mercury thermometer, hydrogen ions (pH) concentration was measured using pH meter (Jenway model 9060) and dissolved oxygen (DO) concentration was measured weekly by an oxygen meter (Hanna model HI-9142). 2.4. Statistical and chemical analyses Complete randomized design (CRD) was used. Data obtained were subjected to analysis of variance (ANOVA) (Steel and Torrie, 1980). Significant differences in means were evaluated using Duncan's Multiple Range Test (Gomez and Gomez, 1984). Nutrient feed analysis was done by the Method of Association of Official Analytical Chemists (A.O.A.C. 1990). 3. Results Summary of growth performance characteristics and water quality results are presented in Tables 2 and 3 respectively.
2.3. Parameters measured 3.1. Growth performance Batch weighing of fish in each replicate aquarium was done at the beginning of the experiment, thereafter biweekly, using a Mettle P20110 top-loading balance. 2.3.1. Growth performance Growth performances were evaluated according to Olivera et al. (1990) as follows:
Fingerlings of C. gariepinus cultured in darkness (24 hour DD) had significantly (P b 0.05) higher weight gain than those cultured in 12 hour DL and 24 hour LL. Also there was significant (P b 0.05) increase in the SGR of fingerlings of C. gariepinus cultured in 24 hour darkness. This followed the same pattern with weight gain. 3.2. Feed utilization
Weight gain ¼ final body weight−initial body weight
ð1Þ
−1 Specific growth rate SGRk day ¼
ðloge final body weight− loge initial body weight Þ 100 TimeðdaysÞ
Feed conversion ratioðFCRÞ ¼
Dry weight of feed eatenðgÞ Fish weight gainðgÞ
Protein efficiency ratioðPERÞ ¼
Percentage survival ¼
Fish weight gainðgÞ Protein fedðgÞ
ð2Þ
ð3Þ
ð4Þ
ðInitial number of fish stocked−mortalityÞ Initial number of fish stocked 100 ð5Þ
Culture of C. gariepinus fingerlings under different photoperiods significantly (P b 0.05) affected feed intake, quantity of uneaten feed, feed conversion ratio (FCR) and protein efficiency ratio (PER). The fingerlings cultured under 24 h of darkness had significant (P b 0.05) highest feed intake, PER, best FCR and lowest quantity of uneaten feed than those cultured under 12 hour DL and 24 hour LL. Generally, as the
Table 3 Water quality analysis of fingerlings of C. gariepinus cultured under different photoperiods (mean ± SEM) Parameters
pH Temperature (°C) Dissolved oxygen (mg/l)
Photoperiods DD
DL
LL
± SEM
6.79 27.65 3.20b
6.86 27.00 6.25a
6.93 27.15 6.26a
0.02 1.84 0.23
Mean with the same superscripts in horizontal row are not significantly different (P N 0.05).
66
M.A. Adewolu et al. / Aquaculture 283 (2008) 64–67
length of exposure of the fish to photoperiod increased from 12 h to 24 h there were proportionate decreases in feed intake, as evident in the quantity of uneaten feed. 3.3. Survival There was significant (P b 0.05) increase in the percentage survival of C. gariepinus fingerlings from 81.00 to 93.89 ± 0.01% as the length of photoperiod exposure decreased.
The low intake of feed resulted to low availability of nutrient for tissue synthesis. This in turn led to reduced weight gain in the illuminated groups. The results obtained in this study seem to suggest that the more the length of exposure of C. gariepinus to light, the lower the feed intake and growth and the more the feed wastage. It has been suggested that effective waste management can be achieved through reduction of feed wastes (Cho and Bureau, 1997), therefore culturing of C gariepinus in darkness may reduce aquaculture waste. 4.2. Feed utilization
3.4. Water quality Water temperature and pH concentration were not significantly (P N 0.05) affected when fingerlings of the C. gariepinus were cultured under different photoperiods. However, when fingerlings were cultured in 24 hour darkness, there was significant (P b 0.05) reduction in the dissolved oxygen concentration of water from 5.75 mg/L in 24 hour light to 3.20 mg/L in the 24 hour darkness. There were no significant (P N 0.05) differences in the dissolved oxygen concentration of the water of fingerlings reared in 12 h of light and 24 h of light. 3.5. Observations Routine observation in the course of this study period showed that fingerlings cultured in 12 h of photoperiod had dark coloration on the dorsal parts and flanks as well as light tinges of grey dotting at the flanks. Fingerlings cultured in 24 h of light were lighter in colour, while those cultured in 24 h of darkness had shiny black colouration, typical of fish in their natural habitat. The black shiny colouration was noticeable after seven (7) days of culture. No clustering behaviour was observed with fingerlings reared in 24 hour darkness while this was observed with fingerlings cultured in 24 h of light. 4. Discussion A full understanding and application of photoperiod restriction may go a long way in improving productivity and sustainability of aquaculture. Photoperiod requirement is extremely variable, can be with or without effect and is related to environmental adaptation, species and age specific (Britz and Pienaar, 1992; Silva-Garcial, 1996; Boeuf and Bail, 1999). 4.1. Growth performance The total biomass or yield of fish affects profitability of aquaculture venture. It can be deduced from this study that as the length of exposure of C. gariepinus fingerlings to photoperiod was reduced, there was increase in the fish weight. The highest weight gain of fish observed in 24 hour darkness than those in12 hour DL and 24 hour LL could not have been due to the quality of feed consumed. This is because the same feed (35% crude protein) was given. However, since weight attained is usually proportional to the quality and quantity of feed given, the increased feed intake by fingerlings in 24 hour darkness may have been responsible for the highest weight gain observed in this group. This result gives credence to the claim that African catfish (C. gariepinus) are photophobic and that they eat comfortably in the dark (Hogendoorn et al., 1980; Britz and Pienaar,1992, Appelbaum,1995; Appelbaum and Mcgeer,1998). The lower weight gain observed with the fingerlings cultured in 12 and 24 h of light might be due to the innate behaviour and stress characteristics of the fish. These behaviours may probably have affected their feed intake as their length of exposure to light increased. This is in line with the reports of Britz and Pienaar (1992), Appelbaum and Kamler (2000), Almazan-Rueda et al. (2004) who observed that swimming and aggressive behaviours increased as the fry and juveniles of C. gariepinus were exposed to light and that as the length of exposure to light increased the fish had less resting time.
The improved feed utilization in the fingerlings of C. gariepinus cultured in 24 hour darkness is reflected in highest values of protein efficiency ratio and specific growth rate and lowest value of feed conversion ratio when compared with those cultured in 12 and 24 h of light. This trend further attests to the claim that C. gariepinus perform best when reared in darkness. Fish growth and feed conversion ratio are closely related, growth is influenced through better feed conversion efficiency and not only through stimulated feed intake (Boeuf and Bail, 1999). This might have been achieved due to lesser energy (nutrients) channeled into locomotor activities (searching for cover, swimming and aggressive behaviours) and more energy (nutrients) channeled into growth as earlier reported by Jørgensen and Jobling (1993), Hecht and Uys (1997), Appelbaum and Kamler (2000) and Almazan-Rueda et al. (2004). Since the fingerlings cultured under the two photoperiods spent more energy in locomotor activities, less energy would have been made available for growth. The more the energy spent on locomotor activities the less the energy available for growth, hence the reduced efficiencies observed as the length of exposure to photoperiod increased from 12 h to 24 h. 4.3. Survival Generally, the fingerlings of C. gariepinus cultured under different photoperiods had high survival (81.00–93.89%). The high survival further confirms the adequacy of the quality of feed given as well as other husbandry methods employed. However, higher survival was obtained in the fingerlings cultured under 24 h of darkness. This finding is in agreement with the reports of Appelbaum and Mcgeer (1998), Appelbaum and Kamler (2000). As earlier explained, when C. gariepinus were cultured in darkness the fish ate comfortably, spent more time resting, which have been implicated in the high feed intake, low wastage and better growth. These may have reduced stress (Odunze et al., 2000), culminating in high survival as against the fingerlings cultured in 12 and 24 hour photoperiods. The gradual reduction in percentage survival as the length of exposure to photoperiod increased seem to suggest that there was a gradual increase in the stress experienced by the fish or that they became less comfortable leading to reduction in survival. As observed in this study aggressive behaviours increased as the length of exposure to photoperiod increased, further confirming that the fingerlings were stressed. 4.4. Water quality The water temperature and pH values of 27–28.15 ± 1.84 °C and 6.7–6.93 ± 0.02 respectively recorded in this study are within the recommended ranges reported by Viveen et al. (1986) for the culture of C. gariepinus. These values increased insignificantly (P N 0.05) as the period of exposure of fingerlings to light increases. However, fingerlings cultured in the darkness had significantly (P b 0.05) reduced the dissolved oxygen concentration of 3.20 ± 0.23mg/L. This confirms the ability of C. gariepinus to withstand low dissolved oxygen concentration. The low dissolved oxygen observed in this group may be connected to the increased weight gains, which necessitated high oxygen demand. This is beside the fact that the culturing environment did not encourage photosynthesis, which could have boosted oxygen
M.A. Adewolu et al. / Aquaculture 283 (2008) 64–67
availability, when compared with the groups of fingerlings cultured under increasing length of photoperiods where there were tendencies for photosynthesis. 5. Conclusion The results of this study showed that photoperiod plays an important role in the feed utilization, growth and survival of C. gariepinus fingerlings. The fingerlings cultured in 24 hour darkness did not only have high feed intake and utilization, as well as increased weight gain and survival, but also minimized feed wastages. The low feed wastages could be a vital tool in reduction of aquaculture solid waste, which presently poses a serious threat to the sustainability of aquaculture (Cho and Bureau, 1997; 2001). Also the shining black colouration observed among the fingerlings in 24 hour darkness is typical of the fish in their natural habitat (Holden and Reed, 1978). This may be an added incentive which could boost consumers' acceptability especially in an emerging aquaculture. However, the low dissolved oxygen concentration observed in 24 hour darkness calls for continuous water renewal of the culturing unit, through the use of recirculatory or flow-through system or by the use of mechanical aeration. Consequently, the implied application of the results of this study showed that total darkness (24 h) could be recommended as a simple low-cost technique for intensification of C. gariepinus production, acceptability and solid waste management. References Almazan-Rueda, P. 2004. Towards assessment of welfare in African catfish, Clarias gariepinus: The first step. PhD dissertation, Wageningen University, Wageningen, The Netherlands. Almazan-Rueda, P., Schrama, J.W., Verreth, J.A.J., 2004. Behavioural responses under different feeding methods and light regimes of the African catfish (Clarias gariepinus) juveniles. Aquaculture 231, 347–359. A.O.A.C., 1990. Official Method of Analysis, 15th edition. Association of official Analytical Chemists, Washington, D.C. Appelbaum, S., 1995. Interactions between feed and feeding behaviour in larval fish. Proc. Aquac. Ass. Con 2, 20–24. Appelbaum, S., Kamler, E., 2000. Survival, growth, metabolism and behaviour of Clarias gariepinus (Burchell 1822) early stages under different light conditions. Aquac. Eng. 22, 269–287.
67
Appelbaum, S., Mcgeer, J.C., 1998. Effect of diet and light regime on growth and survival of African catfish (Clarias gariepinus) larvae and early juveniles. Aquac. Nutr. 4, 157–164. Boeuf, G., Bail le, P.Y., 1999. Does light have an influence on fish growth? Aquaculture 177, 129–152. Britz, P.J., Pienaar, A.G., 1992. Laboratory experiments on effect of light and cover on the behaviour and growth of African catfish, Clarias gariepinus (Pisces: Claridae). J. Zool. Lond. 227, 43–62. Cho, C.Y., Bureau, D.P., 1997. Reduction of waste output from salmonid aquaculture through feeds and feeding. Prog. Fish-Cult. 59, 155–160. Cho, C.Y., Bureau, D.P., 2001. A review of dietary formulation strategies and feeding systems to reduce excretory and feed wastes in aquaculture. Aquac. Res. 32, 349–360 (SI). Gomez, A.K., Gomez, A.A., 1984. Statistical Procedures for Agricultural Research Copyright. John Wiley and Sons Inc, p. 304. Hecht, T., Appelbaum, S., 1988. Observations on intraspecific aggression and coeval sibling, cannibalism in juvenile Clarias gariepinus (Clariidae Pisces) under controlled conditions. J. Zool. (Lond.) 214, 21–44. Hecht, T., Uys, W., 1997. Effect of density on the feeding and aggressive behaviour in juvenile African catfish, Clarias gariepinus S. Afr. J. Sci. 93, 537–541. Hogendoorn, H., Hardeman, G.J., Vismans, M.M., Viveen, W.J.A.R., 1980. Controlled propagation of the labyrinthic catfish, Clarias lazera (C and V) for experiment purposes. Proceedings of the 7th ICLAS Symposium, Utrecht, 1979. Gustav Fisher, Stuttgaart, pp. 363–371. Holden, M., Reed, W., 1978. West African Freshwater Fish, 2nd edition. Longman group Ltd, London. 68 pp. Jørgensen, E.H., Jobling, M., 1993. Feeding in darkness eliminates density-dependent growth suppression in a Arctic charr. Aquac. Int. 1, 90–93. Nwosu, F.M., Holzlöhner, S., 2000. Effect of stocking density on growth, survival of Heterobranchus longifilis Val. 1840 Co (Teleostei: Clariidae) larvae after 14 days of rearing. J. Appl. Ichthyol. 16, 24–26. Odunze, F.C., Ibiwoye, T.I.J., Ladu, B.M.B., Iyolyyoon, P., 2000. Preliminary studies on the effects of light duration on the growth and performance of Clarias gariepinus fingerlings. NIFFER Annual Report, pp. 33–35. Ogbe, F.G., Annune, P.A., Soremi, O.A., 2001. Aquaculture development in Benue State. Technology and Socio-economic states. J. Res. Rev. Sci. 2, 289–291. Olivera, N.M.A., Campos, G.S., Sabido, G.M., Martinez, P.C.A., 1990. The use of alfalfa leaf protein concentrates as protein source in diets for tilapia (Oreochromis mossambicus). Aquaculture 90, 291–302. Silva-Garcial, A.J., 1996. Growth of juvenile gilthead seabream (Sparus aurata L.) reared under different photoperiod regimes. Isr. J. Aquac. -Bamidgeh 48, 84–93. Steel, R.G.D., Torrie, J.H., 1980. Principles and Procedure of Statistics, 2nd ed. McGraw Hill Book Comp, N.Y. U.S.A. 87 pp. Van Weerd, J.H., 1995. Nutrition and growth in Clarias species—a review. Aqual. Living Resour. 8, 395–401. Viveen, W.J.A., Richter, C.J.J., Van Oordt, P.G., Janseen, J.A.L., Huisman, E.A., 1986. Practical manual for the culture of African Catfish Clarias gariepinus. Directorate General International Cooperation of the Ministry of Foreign Affairs. The Hague, Netherlands. 121 pp.
Contents lists available at ScienceDirect
Aquaculture j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / a q u a - o n l i n e
Feed utilization, growth and survival of Clarias gariepinus (Burchell 1822) fingerlings cultured under different photoperiods Morenike A. Adewolu ⁎, Comfort A. Adeniji, Ademola B. Adejobi Fisheries Dept, Faculty of Science, Lagos State University, P.M.B 00I,LASU Post Office, Badagry Expressway, Ojo, Lagos, Nigeria
a r t i c l e
i n f o
Article history: Received 10 March 2008 Received in revised form 13 July 2008 Accepted 14 July 2008 Keywords: Photoperiods Clarias gariepinus Growth Feed utilization Survival
a b s t r a c t This study assessed the effects of three photoperiods on growth, feed utilization and survival of African catfish, Clarias gariepinus fingerlings. Fish of initial weight 1.15 ± 0.03 g(mean ± SEM) were exposed to 24 h of darkness (DD), 12 h of darkness and 12 h of light (DL) and 24 h of light (LL) for a period of 70 days in a partial flow-through system. The fingerlings were cultured in triplicate groups and fed on 35% crude protein prepared diet at 5% body weight. Fingerlings reared in darkness (DD) had significantly (P b 0.05) highest feed intake, weight gain, protein efficiency ratio, specific growth rate and percentage survival followed by fingerlings cultured in DL which were significantly (P b 0.05) higher than those in LL. Also, the fingerlings cultured in DD had significantly (P b 0.05) lowest uneaten feed and feed conversion ratio, than those reared in DL and LL. There were no significant (P N 0.05) differences in the water temperature and pH of fingerlings cultured under the three different photoperiods, however, dissolved oxygen concentration was significantly (P b 0.05) reduced when the fingerlings were cultured in 24 hour darkness. Fish cultured in DD had darker skin colorations than those in LL. The results of this study show that growth, feed utilization and survival of C. gariepinus fingerlings were improved when cultured in 24 h of darkness. © 2008 Elsevier B.V. All rights reserved.
1. Introduction Photoperiod is known to affect fish feeding activity and play a decisive role in growth and survival (Nwosu and Holzlöhner, 2000). It has the tendency to influence the overall fish performance. Consequently, correct application of photoperiod may improve performance, profitability and sustainability of aquacultural practices. The African catfish (Clarias gariepinus) is one of the most important fish species currently being cultured both within and outside its natural range of tropical and subtropical environments. Its ability to breathe air and withstand poor water quality as well as its high consumer acceptability and tasty flesh makes it of commercial importance (Hecht and Appelbaum, 1988; Van Weerd, 1995; Appelbaum and Kamler, 2000). Britz and Pienaar (1992) reported that restriction of light may be used in its culture to enhance growth and reduce stress, this collaborates the view of Ogbe et al. (2001) who reported that C. gariepinus are bottom feeders that feed comfortably in the dark. These seem to suggest that light plays a major role in regulating the activities of C. gariepinus particularly feeding (Nwosu and Holzlöhner, 2000; Appelbaum and Mcgeer, 1998) and growth. The effect of photoperiod on growth and survival of C. gariepinus at the larval stage has been demonstrated by several authors (Britz and Pienaar, 1992; Appelbaum and Kamler, 2000; Appelbaum and Mcgeer, ⁎ Corresponding author. Tel.: +234 803 056 7600. E-mail address: [email protected] (M.A. Adewolu). 0044-8486/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.aquaculture.2008.07.020
1998; Almazan-Rueda, 2004). However, there is paucity of information on the effect of photoperiod at the fingerling stage; more so that photoperiod is both species and age specific (Boeuf and Bail, 1999). Thus the need to establish the influence of different photoperiods on the performance of C. gariepinus, especially in a rapidly emerging aquaculture industry as obtains in Nigeria. It is against this background that this study was designed to establish the effect of different photoperiods on the growth, feed utilization and survival of C. gariepinus fingerlings. 2. Materials and methods 2.1. Experimental design Three photoperiods: 24 h of darkness (DD), 12 h of darkness and 12 h of light (DL) and 24 h of light (LL) were used as experimental treatments. Triplicate rearing facilities (aquaria) with capacity for 80 L of water and 0.5 m in depth were used for each treatment. Black cellophane polyethylene materials were used to cover off the rearing units to provide 24 h of darkness. The darkened tanks had small holes (3.0 cm) on the cover for food administration as demonstrated by Appelbaum and Mcgeer (1998).The holes were covered immediately after feeding. Normal day was taken as 12 h of light and 12 h of darkness, while rechargeable fluorescent light of 20 W were used to provide light for the remaining 12 h of darkness to give 24 h of continuous light.
M.A. Adewolu et al. / Aquaculture 283 (2008) 64–67
65
Table 1 Percentage composition of prepared feed fed to fingerlings of C. gariepinus reared under different photoperiods
Table 2 Summary of growth and feed utilization of fingerlings cultured under different photoperiods (mean ± SEM)
Ingredients
Percentage incorporation
Parameters
Maize Soybean meal Fish meal Wheat offal Oil Dicalcium phosphate Vitamin/mineral premixa Vitamin C Salt Determined crude protein
33.00 40.00 16.00 7.75 1.00 1.00 0.50 0.50 0.25 35.00
Initial weight/fingerling Weight gain/fish (g) Final weight/fish (g) Specific growth rate Feed consumed/fish (g) Uneaten feed/fish (mg) Feed conversion ratio Protein efficiency ratio Survival percentage
a Each kg of the diet contained 2,000,000 IU vit. A; 4,000,000 IU vit. D3; 200,000 vit. E; 1,200 mg vit. K; 10,000 mg vit. B1; 30,000 mg vit. B2; 19,000 mg vit. B6; 1000 mg vit. B12; 5000 mg Panthotenic acid; 200,000 mg Niacin; 5,000 mg Folic acid; 30 g Mn; 40 g Zn; 40 mg Fe;4 g Cu; 5 g I2; 0.2 mg Co; 600 g calcium; 400 mg choline chloride; 40 mg biotin; 400,000 mg phosphorus; 100,000 mg lysine; 400 g methionine and 125 IU antioxidant.
2.2. Fish management Twenty one (21) day old of C. gariepinus fingerlings of initial weight 1.15 ± 0.03 g (mean ± SEM) and length 4.30 ± 0.20 cm were obtained from the Lagos State University hatchery for the study. The fingerlings were acclimatized for 5 days prior to the start of the experiment and were randomly distributed to nine 80 L aquaria of 0.5 m depth at the stocking rate of 20 fingerlings per aquarium in triplicate, in a partial flow-through system such that daily, there was 50% water exchange to prevent ammonia buildup. The facilities were aerated by means of electric air pumps with air stones throughout the seventy (70) days study period. The fingerlings were fed on a 35% crude protein prepared diet at 5% body weight twice daily at 09.00 h and 18.00 h. The percentage composition of the experimental diet is shown in Table 1. About 30 min after feeding, leftover feed were collected by briefly removing the standpipe at the end of the tank. The outflow was filtered through Whatman filter paper number 1 of 110 mm in diameter. The filtrates (uneaten feed) were air dried, stored and weighed.
Photoperiods DD
DL
LL
± SEM
1.15 1.84a 2.99a 1.37a 3.07a 50c 1.66c 1.73a 93.89a
1.14 1.35b 2.48b 1.12b 2.72b 90b 2.02b 1.42b 88.22b
1.14 0.76c 1.89c 0.86c 2.32c 150a 3.05a 0.94c 81.00c
0.03 0.01 0.01 0.10 0.05 0.05 0.02 0.01 0.01
Mean with the same superscripts in horizontal row are not significantly different (P N 0.05).
2.3.2. Water quality analysis Water temperature in the experimental system was measured daily by using a mercury thermometer, hydrogen ions (pH) concentration was measured using pH meter (Jenway model 9060) and dissolved oxygen (DO) concentration was measured weekly by an oxygen meter (Hanna model HI-9142). 2.4. Statistical and chemical analyses Complete randomized design (CRD) was used. Data obtained were subjected to analysis of variance (ANOVA) (Steel and Torrie, 1980). Significant differences in means were evaluated using Duncan's Multiple Range Test (Gomez and Gomez, 1984). Nutrient feed analysis was done by the Method of Association of Official Analytical Chemists (A.O.A.C. 1990). 3. Results Summary of growth performance characteristics and water quality results are presented in Tables 2 and 3 respectively.
2.3. Parameters measured 3.1. Growth performance Batch weighing of fish in each replicate aquarium was done at the beginning of the experiment, thereafter biweekly, using a Mettle P20110 top-loading balance. 2.3.1. Growth performance Growth performances were evaluated according to Olivera et al. (1990) as follows:
Fingerlings of C. gariepinus cultured in darkness (24 hour DD) had significantly (P b 0.05) higher weight gain than those cultured in 12 hour DL and 24 hour LL. Also there was significant (P b 0.05) increase in the SGR of fingerlings of C. gariepinus cultured in 24 hour darkness. This followed the same pattern with weight gain. 3.2. Feed utilization
Weight gain ¼ final body weight−initial body weight
ð1Þ
−1 Specific growth rate SGRk day ¼
ðloge final body weight− loge initial body weight Þ 100 TimeðdaysÞ
Feed conversion ratioðFCRÞ ¼
Dry weight of feed eatenðgÞ Fish weight gainðgÞ
Protein efficiency ratioðPERÞ ¼
Percentage survival ¼
Fish weight gainðgÞ Protein fedðgÞ
ð2Þ
ð3Þ
ð4Þ
ðInitial number of fish stocked−mortalityÞ Initial number of fish stocked 100 ð5Þ
Culture of C. gariepinus fingerlings under different photoperiods significantly (P b 0.05) affected feed intake, quantity of uneaten feed, feed conversion ratio (FCR) and protein efficiency ratio (PER). The fingerlings cultured under 24 h of darkness had significant (P b 0.05) highest feed intake, PER, best FCR and lowest quantity of uneaten feed than those cultured under 12 hour DL and 24 hour LL. Generally, as the
Table 3 Water quality analysis of fingerlings of C. gariepinus cultured under different photoperiods (mean ± SEM) Parameters
pH Temperature (°C) Dissolved oxygen (mg/l)
Photoperiods DD
DL
LL
± SEM
6.79 27.65 3.20b
6.86 27.00 6.25a
6.93 27.15 6.26a
0.02 1.84 0.23
Mean with the same superscripts in horizontal row are not significantly different (P N 0.05).
66
M.A. Adewolu et al. / Aquaculture 283 (2008) 64–67
length of exposure of the fish to photoperiod increased from 12 h to 24 h there were proportionate decreases in feed intake, as evident in the quantity of uneaten feed. 3.3. Survival There was significant (P b 0.05) increase in the percentage survival of C. gariepinus fingerlings from 81.00 to 93.89 ± 0.01% as the length of photoperiod exposure decreased.
The low intake of feed resulted to low availability of nutrient for tissue synthesis. This in turn led to reduced weight gain in the illuminated groups. The results obtained in this study seem to suggest that the more the length of exposure of C. gariepinus to light, the lower the feed intake and growth and the more the feed wastage. It has been suggested that effective waste management can be achieved through reduction of feed wastes (Cho and Bureau, 1997), therefore culturing of C gariepinus in darkness may reduce aquaculture waste. 4.2. Feed utilization
3.4. Water quality Water temperature and pH concentration were not significantly (P N 0.05) affected when fingerlings of the C. gariepinus were cultured under different photoperiods. However, when fingerlings were cultured in 24 hour darkness, there was significant (P b 0.05) reduction in the dissolved oxygen concentration of water from 5.75 mg/L in 24 hour light to 3.20 mg/L in the 24 hour darkness. There were no significant (P N 0.05) differences in the dissolved oxygen concentration of the water of fingerlings reared in 12 h of light and 24 h of light. 3.5. Observations Routine observation in the course of this study period showed that fingerlings cultured in 12 h of photoperiod had dark coloration on the dorsal parts and flanks as well as light tinges of grey dotting at the flanks. Fingerlings cultured in 24 h of light were lighter in colour, while those cultured in 24 h of darkness had shiny black colouration, typical of fish in their natural habitat. The black shiny colouration was noticeable after seven (7) days of culture. No clustering behaviour was observed with fingerlings reared in 24 hour darkness while this was observed with fingerlings cultured in 24 h of light. 4. Discussion A full understanding and application of photoperiod restriction may go a long way in improving productivity and sustainability of aquaculture. Photoperiod requirement is extremely variable, can be with or without effect and is related to environmental adaptation, species and age specific (Britz and Pienaar, 1992; Silva-Garcial, 1996; Boeuf and Bail, 1999). 4.1. Growth performance The total biomass or yield of fish affects profitability of aquaculture venture. It can be deduced from this study that as the length of exposure of C. gariepinus fingerlings to photoperiod was reduced, there was increase in the fish weight. The highest weight gain of fish observed in 24 hour darkness than those in12 hour DL and 24 hour LL could not have been due to the quality of feed consumed. This is because the same feed (35% crude protein) was given. However, since weight attained is usually proportional to the quality and quantity of feed given, the increased feed intake by fingerlings in 24 hour darkness may have been responsible for the highest weight gain observed in this group. This result gives credence to the claim that African catfish (C. gariepinus) are photophobic and that they eat comfortably in the dark (Hogendoorn et al., 1980; Britz and Pienaar,1992, Appelbaum,1995; Appelbaum and Mcgeer,1998). The lower weight gain observed with the fingerlings cultured in 12 and 24 h of light might be due to the innate behaviour and stress characteristics of the fish. These behaviours may probably have affected their feed intake as their length of exposure to light increased. This is in line with the reports of Britz and Pienaar (1992), Appelbaum and Kamler (2000), Almazan-Rueda et al. (2004) who observed that swimming and aggressive behaviours increased as the fry and juveniles of C. gariepinus were exposed to light and that as the length of exposure to light increased the fish had less resting time.
The improved feed utilization in the fingerlings of C. gariepinus cultured in 24 hour darkness is reflected in highest values of protein efficiency ratio and specific growth rate and lowest value of feed conversion ratio when compared with those cultured in 12 and 24 h of light. This trend further attests to the claim that C. gariepinus perform best when reared in darkness. Fish growth and feed conversion ratio are closely related, growth is influenced through better feed conversion efficiency and not only through stimulated feed intake (Boeuf and Bail, 1999). This might have been achieved due to lesser energy (nutrients) channeled into locomotor activities (searching for cover, swimming and aggressive behaviours) and more energy (nutrients) channeled into growth as earlier reported by Jørgensen and Jobling (1993), Hecht and Uys (1997), Appelbaum and Kamler (2000) and Almazan-Rueda et al. (2004). Since the fingerlings cultured under the two photoperiods spent more energy in locomotor activities, less energy would have been made available for growth. The more the energy spent on locomotor activities the less the energy available for growth, hence the reduced efficiencies observed as the length of exposure to photoperiod increased from 12 h to 24 h. 4.3. Survival Generally, the fingerlings of C. gariepinus cultured under different photoperiods had high survival (81.00–93.89%). The high survival further confirms the adequacy of the quality of feed given as well as other husbandry methods employed. However, higher survival was obtained in the fingerlings cultured under 24 h of darkness. This finding is in agreement with the reports of Appelbaum and Mcgeer (1998), Appelbaum and Kamler (2000). As earlier explained, when C. gariepinus were cultured in darkness the fish ate comfortably, spent more time resting, which have been implicated in the high feed intake, low wastage and better growth. These may have reduced stress (Odunze et al., 2000), culminating in high survival as against the fingerlings cultured in 12 and 24 hour photoperiods. The gradual reduction in percentage survival as the length of exposure to photoperiod increased seem to suggest that there was a gradual increase in the stress experienced by the fish or that they became less comfortable leading to reduction in survival. As observed in this study aggressive behaviours increased as the length of exposure to photoperiod increased, further confirming that the fingerlings were stressed. 4.4. Water quality The water temperature and pH values of 27–28.15 ± 1.84 °C and 6.7–6.93 ± 0.02 respectively recorded in this study are within the recommended ranges reported by Viveen et al. (1986) for the culture of C. gariepinus. These values increased insignificantly (P N 0.05) as the period of exposure of fingerlings to light increases. However, fingerlings cultured in the darkness had significantly (P b 0.05) reduced the dissolved oxygen concentration of 3.20 ± 0.23mg/L. This confirms the ability of C. gariepinus to withstand low dissolved oxygen concentration. The low dissolved oxygen observed in this group may be connected to the increased weight gains, which necessitated high oxygen demand. This is beside the fact that the culturing environment did not encourage photosynthesis, which could have boosted oxygen
M.A. Adewolu et al. / Aquaculture 283 (2008) 64–67
availability, when compared with the groups of fingerlings cultured under increasing length of photoperiods where there were tendencies for photosynthesis. 5. Conclusion The results of this study showed that photoperiod plays an important role in the feed utilization, growth and survival of C. gariepinus fingerlings. The fingerlings cultured in 24 hour darkness did not only have high feed intake and utilization, as well as increased weight gain and survival, but also minimized feed wastages. The low feed wastages could be a vital tool in reduction of aquaculture solid waste, which presently poses a serious threat to the sustainability of aquaculture (Cho and Bureau, 1997; 2001). Also the shining black colouration observed among the fingerlings in 24 hour darkness is typical of the fish in their natural habitat (Holden and Reed, 1978). This may be an added incentive which could boost consumers' acceptability especially in an emerging aquaculture. However, the low dissolved oxygen concentration observed in 24 hour darkness calls for continuous water renewal of the culturing unit, through the use of recirculatory or flow-through system or by the use of mechanical aeration. Consequently, the implied application of the results of this study showed that total darkness (24 h) could be recommended as a simple low-cost technique for intensification of C. gariepinus production, acceptability and solid waste management. References Almazan-Rueda, P. 2004. Towards assessment of welfare in African catfish, Clarias gariepinus: The first step. PhD dissertation, Wageningen University, Wageningen, The Netherlands. Almazan-Rueda, P., Schrama, J.W., Verreth, J.A.J., 2004. Behavioural responses under different feeding methods and light regimes of the African catfish (Clarias gariepinus) juveniles. Aquaculture 231, 347–359. A.O.A.C., 1990. Official Method of Analysis, 15th edition. Association of official Analytical Chemists, Washington, D.C. Appelbaum, S., 1995. Interactions between feed and feeding behaviour in larval fish. Proc. Aquac. Ass. Con 2, 20–24. Appelbaum, S., Kamler, E., 2000. Survival, growth, metabolism and behaviour of Clarias gariepinus (Burchell 1822) early stages under different light conditions. Aquac. Eng. 22, 269–287.
67
Appelbaum, S., Mcgeer, J.C., 1998. Effect of diet and light regime on growth and survival of African catfish (Clarias gariepinus) larvae and early juveniles. Aquac. Nutr. 4, 157–164. Boeuf, G., Bail le, P.Y., 1999. Does light have an influence on fish growth? Aquaculture 177, 129–152. Britz, P.J., Pienaar, A.G., 1992. Laboratory experiments on effect of light and cover on the behaviour and growth of African catfish, Clarias gariepinus (Pisces: Claridae). J. Zool. Lond. 227, 43–62. Cho, C.Y., Bureau, D.P., 1997. Reduction of waste output from salmonid aquaculture through feeds and feeding. Prog. Fish-Cult. 59, 155–160. Cho, C.Y., Bureau, D.P., 2001. A review of dietary formulation strategies and feeding systems to reduce excretory and feed wastes in aquaculture. Aquac. Res. 32, 349–360 (SI). Gomez, A.K., Gomez, A.A., 1984. Statistical Procedures for Agricultural Research Copyright. John Wiley and Sons Inc, p. 304. Hecht, T., Appelbaum, S., 1988. Observations on intraspecific aggression and coeval sibling, cannibalism in juvenile Clarias gariepinus (Clariidae Pisces) under controlled conditions. J. Zool. (Lond.) 214, 21–44. Hecht, T., Uys, W., 1997. Effect of density on the feeding and aggressive behaviour in juvenile African catfish, Clarias gariepinus S. Afr. J. Sci. 93, 537–541. Hogendoorn, H., Hardeman, G.J., Vismans, M.M., Viveen, W.J.A.R., 1980. Controlled propagation of the labyrinthic catfish, Clarias lazera (C and V) for experiment purposes. Proceedings of the 7th ICLAS Symposium, Utrecht, 1979. Gustav Fisher, Stuttgaart, pp. 363–371. Holden, M., Reed, W., 1978. West African Freshwater Fish, 2nd edition. Longman group Ltd, London. 68 pp. Jørgensen, E.H., Jobling, M., 1993. Feeding in darkness eliminates density-dependent growth suppression in a Arctic charr. Aquac. Int. 1, 90–93. Nwosu, F.M., Holzlöhner, S., 2000. Effect of stocking density on growth, survival of Heterobranchus longifilis Val. 1840 Co (Teleostei: Clariidae) larvae after 14 days of rearing. J. Appl. Ichthyol. 16, 24–26. Odunze, F.C., Ibiwoye, T.I.J., Ladu, B.M.B., Iyolyyoon, P., 2000. Preliminary studies on the effects of light duration on the growth and performance of Clarias gariepinus fingerlings. NIFFER Annual Report, pp. 33–35. Ogbe, F.G., Annune, P.A., Soremi, O.A., 2001. Aquaculture development in Benue State. Technology and Socio-economic states. J. Res. Rev. Sci. 2, 289–291. Olivera, N.M.A., Campos, G.S., Sabido, G.M., Martinez, P.C.A., 1990. The use of alfalfa leaf protein concentrates as protein source in diets for tilapia (Oreochromis mossambicus). Aquaculture 90, 291–302. Silva-Garcial, A.J., 1996. Growth of juvenile gilthead seabream (Sparus aurata L.) reared under different photoperiod regimes. Isr. J. Aquac. -Bamidgeh 48, 84–93. Steel, R.G.D., Torrie, J.H., 1980. Principles and Procedure of Statistics, 2nd ed. McGraw Hill Book Comp, N.Y. U.S.A. 87 pp. Van Weerd, J.H., 1995. Nutrition and growth in Clarias species—a review. Aqual. Living Resour. 8, 395–401. Viveen, W.J.A., Richter, C.J.J., Van Oordt, P.G., Janseen, J.A.L., Huisman, E.A., 1986. Practical manual for the culture of African Catfish Clarias gariepinus. Directorate General International Cooperation of the Ministry of Foreign Affairs. The Hague, Netherlands. 121 pp.