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Feeding the right pellet size to tilapia fingerlings
A relationship between growth performance and mouth gape determines the suitable pellet size
By Cuong Huynh Tran, Tran Minh Triet, Truong Thao, Pham Minh Anh and Marc Campet
An optimal feeding program is imperative if we want to utilise formulated feeds and to ensure that they meet the requirements of fish growth performance. The current feeding program is established based on several parameters, such as as fish weight, pellet size, feeding rate and feeding frequency. The pellet size is an important part of this guideline and has been proven to affect the feeding behaviour and response time of fish to the feed. In general, the best growth performance can be achieved with the optimal pellet size while the smaller and larger pellet sizes have resulted in a decrease in growth rate.
Currently, most feeding guidelines have been established based on farmers’ experience without any proper study or observation. The purpose of this paper is to accurately propose a feeding guideline for red tilapia (Oreochromis sp.) fingerlings from newly hatched larvae up to 35g each, including examining the growth performance, measuring the mouth gape and determining the pellet size. At the same time, the compatibility of the reference function for estimating the mouth gape of tilapia fingerlings from a previous study was also examined.
Methodology
This experiment was conducted at the ADM Aquaculture Research and Development Centre in Ho Chi Minh City. Fish were raised in an outdoor facility in six different composite tanks (400L/tank) with a stocking density of 300 fish per tank. On the day of stocking, there was no feeding. In the following days, fish were hand-fed following the manufacturer’s guidelines.
Tilapia fingerlings were then sampled to measure the growth performance and mouth gape twice a week, until they reached 35g. Six tilapia juveniles were collected from each tank, using a net scoop. Water parameters (temperature, pH, dissolved oxygen, nitrite, total ammonia) were measured, using commercial test kits (TMS).
At each sampling, body weight (WG) was measured using a sensitive electronic balance, while the total length was determined by measuring from the tip of the mouth to the end of the dorsal fin using an electronic caliper. The mouth gape (G) was determined either by measuring from the upper jaw to the lower jaw of the fish using a caliper, or by estimation based on their body weight using the linear correlation function: Log10G=0.37×Log10W+0.65, proposed by Fessehaye et al. (2006). The mouth gape was further used for the estimation of pellet size according to the study of Azaza et al. (2010)
Water quality
Water quality parameters collected during the nursery period were not significantly different among tanks. Parameters shown in Table 1 were in an acceptable range for tilapia fingerlings (Benli and Kӧksal, 2005; Wang et al., 2006).
Parameters Average Range
Temperature at 8am (°C) 30°C 28 - 32°C Temperature at 3pm (°C) 31°C 29 - 34°C pH at 8am 7.6 6.8 - 8.2 pH at 3pm 7.5 7.1 - 8.0 Dissolved oxygen at 8am (mg/L) 5.6 mg/L 3.5 - 8 mg/L Dissolved oxygen at 3pm (mg/L) 5.3 mg/L 2.5 - 8.5 mg/L Total ammonia (mg/L) 0.5 mg/L 0.1 - 2.0 mg/L Nitrite (mg/L) 0.1 mg/L 0.0 - 1.0 mg/L
Table 1. Water quality parameters
Growth performance
The results of growth performance indicated that the body weight and total length increased during the nursery Water quality parameters collected during the nursery period were not significantly different among period, as shown in Figure 1. This outcome was supported tanks. Parameters shown in Table 1 were in an acceptable range for tilapia fingerlings (Benli and Kӧksal, by previous tilapia research although the growth rate 2005; Wang et al., 2006). might vary. Growth variation can be explained by nursery Table 1 Water quality parameters conditions, as the stocking density usually ranged from 5 to 500 pieces/m3 . Parameters Temperature at 8am (°C) Average 30°C Range 28 - 32°C
Temperature at 3pm (°C) 31°C 29 - 34°C Mouth gape and pellet size pH at 8am 7.6 6.8 - 8.2 pH at 3pm 7.5 7.1 - 8.0 The mouth gape estimation and measurement are shown in Dissolved oxygen at 8am (mg/L) 5.6 mg/L 3.5– 8 mg/L Figure 2. Tilapia juveniles from 0.5 to 12g had similar mouth Dissolved oxygen at 3pm (mg/L) 5.3 mg/L 2.5 - 8.5 mg/L gape determined by both methods. Subsequently, there were Total ammonia (mg/L) 0.5 mg/L 0.1 - 2.0 mg/L significant differences in mouth gape of fingerlings above Nitrite (mg/L) 0.1 mg/L 0.0 - 1.0 mg/L 12g. Fessehaye’s function in Nile tilapia Oreochromis niloticus generated greater mouth size estimation, compared to the Growth performance actual mouth size measurement in red tilapia. Mouth gape The results of growth performance indicated that body weight and total length increased during the calibrations of red tilapia fingerlings were used to establish a linear regression line based on body weight from 0.5 to nursery period as shown in Figure 1. This outcome was supported by previous tilapia research although the growth rate might vary. Growth variation can be explained by nursery conditions as the stocking density usually ranged from 5 to 500 pieces/m3. In general, tilapia fry took about 3 months to reach 3040g/individual. Figure 1: Development of tilapia juveniles in terms of body weight (g) and total length (cm) during the 78-day nursery phase.Figure 1. Development of tilapia juveniles in terms of body weight (g) and total length (cm) during the 78-day nursery phase.
of mouth gape
10 Log
1.40
1.20
1.00
0.80
0.60
0.40
0.20 y = 0.3427x + 0.6528 R² = 0.9724
0.00 -1.00 -0.50 0.00 0.50 1.00 1.50 2.00 Log10 of body weight
Figure 2. The relationship between mouth gape and pellet size for tilapia juveniles. Figure 2. The relationship between mouth gape and pellet size for tilapia juveniles.
1.40
1.20
y = 0.3427x + 0.6528 R² = 0.9724 35g: Log10G = 0.3427 × Log shown in Figure 3. Recommendations 0.60 0.80 1.00of mouth gape 10W+ 0.6528 (r2 = 0.9724), as In order to achieve a high growth performance, especially 0.40Log 10 at the nursery phase, it is crucial to choose the pellet size 0.20 that matches the mouth gape of fingerlings. This study is an attempt to improve the current feeding program by defining 0.00 -1.00 -0.50 0.00 0.50 1.00 1.50 2.00 the suitable pellet size for tilapia fingerlings mouth gape. Log10 of body weight In our subsequent research, we plan to conduct more indepth studies on various cultured species, using a similar Figure 3. Linear regression between Log10 of body weight and Log10 of mouth gape. methodology. At ADM, we have a long-term strategy to provide quality nutritional solutions that support the fish throughout their lifecycle. Our holistic approach and sophisticated production technology allow us to conduct extensive research as well as to manufacture prominent aquafeeds. We introduce the NANOLIS range that offers precise nutrition with the right particle size for fingerlings. These feeds ensure growth performance for fish to reach their full potential beyond the nursery stage.
Figure 3. Linear regression between Log10 of body weight and Log10 of mouth gape.
size heterogeneity of Nile tilapia Oreochromis niloticus. Journal of Fish Biology, 76(3), 669–683. https://doi.org/10.1111/J.10958649.2009.02524.X Benli, A.ÇK., Kӧksal, G. 2005. The acute toxicity of ammonia on tilapia (Oreochromis niloticus L.) larvae and fingerlings. Turkish Journal of Veterinary & Animal Sciences, 29(2), 339–344. Fessehaye, Y., Kabir, A., Bovenhuis, H., Komen, H. 2006. Prediction of cannibalism in juvenile Oreochromis niloticus based on predator to prey weight ratio, and effects of age and stocking density. Aquaculture, 255(1–4), 314–322. https://doi.org/10.1016/J. Aquaculture.2005.11.033 Wang, Y., Zhang, W., Li, W., Xu, Z. 2006. Acute toxicity of nitrite on tilapia (Oreochromis niloticus) at different external chloride concentrations. Fish Physiology and Biochemistry, 32(1), 49–54. https://doi.org/10.1007/S10695-005-5744-2
3
References
Azaza, M.S., Legendre, M., Kraiem, M.M., Baras, E. 2010. Sizedependent effects of daily thermal fluctuations on the growth and
Figure 4. Overview of the developmental of red tilapia Figure 4. Overview of the developmental of red tilapia Oreochromis sp. during days of Culture (DOC 178) Oreochromis sp. during days of Culture (DOC 1-78) Cuong Huynh Tran is Asia Aquaculture Technical Manager Aquaculture, based in Vietnam. Email: cuonghuynh.tran@adm.com.
Tran Minh Triet is Technical Support Intern, based in Vietnam. Email: triet.tranminh@adm.com
Truong Thao is R&D Manager Asia.
Pham Minh Anh is R&D Director Asia.
Marc Campet is Asia Aquaculture Commercial Manager, based in Vietnam. Email: marc.campet@adm.com
All authors are with ADM Animal Nutrition and its Aquaculture R&D Center, Nha Be district, Ho Chi Minh City, Vietnam.
Recommendations
In order to achieve a high growth performance, especially at the nursery phase, it is crucial to choose the pellet size that matches the mouth gape of fingerlings. This study is an attempt to improve the current feeding program by defining the mouth gape and a suitable pellet size of tilapia fingerlings. In our subsequent research, we plan to conduct more in-depth studies on various cultured species, using a similar methodology. At ADM, we have a long-term strategy to provide quality nutritional solutions that support the fish throughout their lifecycle. Our holistic approach and sophisticated production technology allow us to conduct the extensive research as well as to manufacture prominent aquafeeds. We introduce the NANOLIS range that offers precise nutrition with the right particle size for fingerling mouth gape. These feeds ensure growth performance for fish to reach their full potential beyond the nursery stage. References
