EFFECT OF VITAMIN A ANDD3 SUPPLEMENTAION ON THE GROWTH PERFORMANCE OF NILE TILAPIA (OREOCHROMIS NILOTICUS)

Assiut University web-site: www.aun.edu.eg

EFFECT OF VITAMIN A ANDD₃ SUPPLEMENTAION ON THE GROWTH PERFORMANCE OF NILE TILAPIA (OREOCHROMIS NILOTICUS)

S.Y. HUSSEIN¹;METWALLY M.A² AND ASMAA, A.M. ³

¹Prof. of Fish Physiology –Dept. of Poultry Production –Fac. of Agri. Assiut University

²Prof. of Poultry Nutrition–Dept. of Poultry Production –Fac. of Agri. Assiut University

³Demonstrator.ofPoultry Production Dept. –Fac. of Agri. Assiut University

Received: 13 March 2021;     Accepted:30 April 2021

INTRODUCTION

The shortage of human dietary protein can be provided by fish protein, particularly in developing countries, where protein shortage is serious (FAO, 1983 and Watanabe, 2002).Aquaculture is the fastest

Corresponding author:Asmaa, A.M.

E-mail address:asmaa_bakr57@yahoo.com

Present address:Demonstrator. of Poultry Production Dept. –Fac. of Agri. Assiut University

growing food production sector in the world and produces a variety of products where nowadays it contributes>50% of global seafood production thus reducing the pressure on the capture fisheries industry which has been on a plateau for many decades. (Wing-Keong and Nicholas Romano,2013 and FAO, 2018).

Tilapia is the second most farmed fish where it is one of the most widely and successfully cultured species worldwideover the past decade. So, it is one of the most widely cultivated fish worldwide (Delphino et al., 2019; Machimbirike et al., 2019) which is farmed in>100countries owing to its rapid growth, adaptiveness, and high market value (Prabu et al., 2019). Therefore,currently, almost 6 million metric tons (MT) of tilapia are grown annually worldwide (Fernando Kubitza., 2019a).Nile tilapia (Oreochromis niloticus) has future prospects due to favorable biological properties, such as easy to breed, grow fast, thick and compact meat also tolerant to various environmental conditions and has a broad response to different food sources and high marketability and relatively stable market prices (Wing-Keong and Nicholas Romano,2013 and Mohamadet al., 2021).

It is noteworthy to mention that currently, Egypt is one of the countries where aquaculture is growing fastest with Nile tilapia (Oreochromis niloticus) as the most widely farmed species.

Unfortunately, intensive aqua-farming is accompanied with several problems where dietary costs, infectious diseases and oxygen deficiency come in limiting the production with consequent negative impact on growth, fecundity and productivity (Cavalcanteaet al., 2020, Ahmed and Doaa 2021 and Tolba, 2021).

Adequate nutrition is critical for tilapia growth, feed efficiency, health and immune status, and quality of farmed tilapia (Fernando Kubitza, 2019). Vitamins are organic compounds found in the diet in relatively small quantities for growth, health, and function in fish. Minerals and vitamins are essential for the formation of tilapia bones and act as cofactors of enzymes in several metabolic processes, play specific roles in the acid-base balance of the blood, in the transmission of nerve impulses, and in the formation of metalloproteins like hemoglobin (Fernando Kubitza, 2019b).

Vitamin A is an essential nutrient for the normal growth of fishsince it plays an important role in a range of physiological processes including vision, reproduction, embryogenesis, growth and differentiation and maintenance of epithelial cells (Luis and Ronald 2020).So,many studies indicated that vitamin A deficiency decrease weight gain, specific growth rate and feed utilization of fish (Yangand Kallio 2002).Other studies have showed that adequate levels of vitamin A could increase body weight, body weight gain, specific growth rate and feed intake of fish (Zhang et al., 2017).Moreover, vitamin A deficiency symptoms reported for various fish species include hemorrhages, retarded growth, poor feed efficiency, anorexia, abnormal coloration, bone deformity, fin erosion, exophthalmia, eyes lesions and hemorrhages, increased erythrocyte osmotic fragility, anemia, lethargy and high mortality (Blazer, 1992; NRC, 1993; 2011 and Mohamed et al., 2003).

Indeed, most of vitamins are not synthesized by animals so, they are taken from diet to meet their needs. So, Saleh et al. (1995) reported that the fat soluble vitamins include vitamin A, D, E and K. are well known to be important for vision, metabolic processes, condition factor and growth in fish, and therefore dietary supplementation in the diets of tilapia is essential.

Tilapia is one of the most widely and successfully cultured species worldwide. However, limited information is available with respect to the effects of dietary vitamin A and D₃ on growth of tilapia but new information continues to be published. Thus, this study was conducted to evaluate the influence of various dietary levels of vitamin A and D₃ on growth performance(weight and length), K-value, feed conversion ratio (FCR) and body indices (HSI, SSI and GSI) of Nile tilapia Oreochromisniloticus.

MATERIALS AND METHODS

The present study was carried out at the experimental fish farm belonging to the Poultry Production Department, Faculty of Agriculture,AssiutUniversity. Theexperimental tilapia fish (O. niloticus) were collected from this experimental fish farm. All the fish were clinically normal and in a good health at the start of the experiment.

1- Management of experimental fish:

The experimental fish were adapted for two weeks in floating cages in a water pond. At the start of the experiment, a total number of one hundred and eightyhealthy fish were chosen and weighed and measured the total length. The average body weight and body length were 50.32 ± 1.72 g and 14.11±0.20 cm, respectively. The fish groups (45 fish each, 15 /subgroup) distributed randomly into four experimental groups as follow:

1-The first group wasfed on the basal diet and considered as a control (C),

2-The second group was fed on the basal dietsupplemented with 20000 IUvitamin A/kgdiet(T1),

3 - The third group was fed on the basal diet supplemented with 40000 IUvitamin A/kg diet (T2) and

4-The fourth group was fed on the basal diet supplemented with 10 mgvitamin D₃/kg diet(T3).

2- Diet preparation:

The dry ingredients of the experimental diets were thoroughly grinded, mixed and pelletized. The ingredient composition and calculated analysis of the experimental diet is shown inTable(1). Fish were adapted to the experimental conditions for two weeks on the diet formulated according to Eid and El-Gamal (1996). All the experimental groups were fed the experimental diet twice daily at a rate of 3% of the live body weight of the fish. The feed quantity was readjusted biweekly on the basis of the actual average biomass of the fish in each treatment. The water temperature and pH were measured daily all over the experimental period.

Table 1: Ingredientcomposition and calculated chemical analysis of the basal diet.

Water quality:

The water temperature was 29.80±1.31 and pH was 7.65± 0.52 all over the experimental period. These values are suitable for rearing the Nile tilapia (Oreochromisniloticus) according to Abd-elhamid (2000).

3- Growth parameters:

The individual body weight (g) and total body length (cm) for all fishes per treatment were recorded biweekly.The average body weight gain (ABWG) was estimated according to the following equation:

Average body weight gain = Average final weight (g) –Average initial weight (g)

Averagebody length increment (cm) was estimated according to the following equation

Average length increment(cm)=Average final length(cm)-Average initial length (cm).

Specific growth rate in each treatment over the experimental period was calculated using the formula:

Specific growth rate (SGR)=   

Where: SGR is the specific growth rate (% body weight gain per day), ln(Wf) is the natural log of the mean final weight, ln(W_I) is the natural log of the mean initial weight and itis the time in days.

Condition factor (K- Value) was calculated for individual fish according to the following equation:

Condition factor (K-value)

(Schreek and Moyle, 1990).

Feed conversions were calculated as following equation:

Feed conversion ratio (FCR)   =

The gonad, liver and spleen indices were calculated as follow:

Spleenosomatic index (SSI)=

Gonadosomatic index (GSI) =  

Hepatosomatic index (HSI) =  

4- Statistical analysis:

Analysis of variance was conducted using the general linear models (GLM) procedure of SAS (SAS Institute, 1998 Licensed to University of Maryland, USA. Proprietary Software Release 6.12 TS020). Duncan's multiple range tests was used to compare between means of the control and treated groups (Steel and Terrie, 1980). The model of analysis was as follows:

Yij = μ + Ti + Eij

μ = The overall mean.

Ti = The effect of treatment.

Eij = The random error.

RESULTS AND DISSCUSSION

A- Growth parameters

1- Body weight (BW)and body weight gain (BWG)

The illustrated datain Table (2)showed that there were no significant differences (P>0.05) in average body weight fish at the beginning of the experiment (initial weight) and at the second and fourth weeks of experimental period among all experiment groups and control.

Table 2: Average body weight (g) of O.niloticus fed different experimental diets.

At the sixth week of the experiment, the average body weight of fish group fed 40.000 IU vitamin A(T2)had a superior body weight (P<0.05) as compared with the other groups but less than the control ones. While, at the eighth week there were insignificant (P>0.05) increase in the average body weight for T2 and T3 as compared with T1.At the tenth week, the average body weight of T3 had insignificant (P>0.05) increase comparing with T1 and T2 and no significant (P>0.05) differences between T3 and control ones.

The obtained data concerning average body weight gain of Oreochromis niloticus fed diet supplemented withvitamin A and D₃are presented in Table (3) showed that the averages  body weight gain were 6.82,3.75, 4.26 and -0.53 for C, T1, T2 and T3at the second week. On the fourth week, the average body weight gain of T3 increased insignificantly (P>0.05) ascompared other treated groups and control group.Also, at the sixth and eighth week of the experiment, the average body weight gain of fish group fed 10 mg vitamin D₃/Kg diet (T3) increased insignificantly (P>0.05) as comparing with the other treated fish groups and control ones.

At the tenth week, the average body weight gain of T3 group had a significant (P<0.05) higher value as compared to the other treated groups but insignificant (P>0.05) increase comparing with control ones.

Table 3: Average body weight gain(g) of O.niloticus fed different experimental diets.

2- Body length (BL)and length increment (L I)

The differencesin body length amongthe experimental groups at the start of the experiment were insignificant [(P> 0.05), Table (4)] which indicatethat experimental groups were homogenous at the beginning of the experiment.After two weeks, average body length increased insignificantly (P>0.05)in fish groups fed 40000 IU vitamin A/Kg diet (T2) and fish group fed 10 mg vitamin D₃ (T3) as compared with T2and control group(Table 4).While, on the fourth andsixth week of the experiment, the averagebody length

had no significant (P>0.05) differences between all the treated fish groups and controlones.

Contrary on the eighth week of the experiment, the average body length of the fish group fed 40000IU vitamin A/Kg diet (T2) increased significantly (P<0.05) as compared with T1 but there were insignificant differences between T2 and T3 and control ones.At the tenth week, the average body length of T3 increased significantly (P<0.05)as compared with fish groups of T1 and T2.While, there were no significant (P>0.05) differences between fish group of T3 and control group.

Table 4: Average body length (cm) of O.niloticus fed different experimental diets.

Data are presented in Table (5) showed that the length increment at the second, fourth, sixth, eighth and tenth week of the experiment in the fish groups C, T1, T2 and T3, respectively. Analysis of variance for the length increment (LI) showed that there are no significant (P>0.05) differences in body length increment for all groups.

3-specific growth rate (SGR%/day):   

The illustrated data in Table (6) show that at the specific growth rate (SGR %) of O. niloticus decreased significantly (P<0.05) in fish group fed 10 mg D₃ / Kg diet as compared with the other treated groups and control ones at the second week. While there were no significant (P>0.05) differences between all the treated fish groups and control ones at the fourth, sixth and eighth week. Meanwhile, at the tenth week, the average specific growth rate of T3 increased significantly (P<0.05) as compared with fish group of T2.While, there were no significant (P>0.05) differences in SGR% between fish groups of T3 and T1 and control group.

Table 5: Average body length increment (cm) of O.niloticus fed different experimental diets.

Table 6: Average specific growth rate (SGR %) of O.niloticus fed different experimental diets.

4- Condition factor (K- value):

The obtained results in Table (7) showed that there weresignificant (P<0.05) variations in K-value between T2 and T3 and T1 and control ones at the second week. Otherwise, there weresignificant (P<0.05) differences in condition factor values between treated fish groups and control at the fourth week of the experiment. At the sixth and eighth week there were no significant (P>0.05) variations in K-value of treated fish groups and control ones. While, the condition factor decreased insignificantly (P>0.05) in fish group of T2 but there were no significant (P>0.05) in K-value between T3 and T1 and control group at the tenth week.

Table 7: Average condition factor of O.niloticus fed different experimental diets.

The obtained results in the present study on growth parameters showed that the tested levels of 20000 and 40000 IU vitamin A(T1 and T2) and 10 mg D3/kg diet (T3) had insignificant (P > 0.05) effects on growth parameters (body weight, body weight gain, total length, length increment and condition factor) of Nile tilapia (Oreochromis niloticus) throughout the experimental periods.Mainly weight gain is the most common response variable used to assess dietary requirements for vitamin A.

Some previous studies showed beneficial effects of vitamin A and D₃on growth parameters of O.niloticus. NRC, (1993, 2011) had been earlier reported that vitamin A and D₃ is dietary essential for Nile tilapia and several other fish species.  Similar results were obtained by Saleh et al. (1995) and Guimarães et.al. (2014) on O. niloticus who reported that after two weeks of feeding, fish fed the vitamin A unsupplemented diet exhibited significantly lowest weight gain than those of other treatments. Also, they showed that these parameters were not observed in fish fed diets supplemented with 2500 to 20,000 IU/kg diet vitamin A.Mohamed et al. (2003) observed that diets supplemented with 3,764 mg vitamin A kg^–1 for greasy grouper led to a better weight gain.

Moreover, dietary vitamin A levels up to 5.400 IU kg^–1 influenced final weight and weight gain of fish (P< 0.05) but did not influence feed consumption (Daniela etal., 2009).Salehet al.(1995) also observed that Nile tilapia juveniles fed diets supplemented with 5,000 IU vitamin A kg^–1 presented better weight gain than fish fed diets containing 0, 10,000 or 40,000 IU vitamin A kg^–1.Also, Huet al.(2006) recorded that the dietary vitamin A requirement for juvenile hybrid tilapia was 5850–5670 IU kg⁻¹.

On contrary, Salehetal.(1995) showed that an addition of 5000, 10 000 and 40 000 IU vitamin A for O. niloticus resulted in a body weight gain of 23.9, 21.6 and 13.2 g.while 10000 IU already show signs of metabolic distortion and even higher dosages cause hypervitaminosis. Therefore,they  concluded that 5000 IU vitamin A kg⁻¹ diet covers the requirement of Tilapia nilotica fingerlings, while 10 000 IU already show signs of metabolic distortion and even higher dosages cause hypervitaminosis. In the same trend, Campeche etal.(2009) recorded that dietary levels of vitamin A up to 5.400 IU kg^-1 influenced final weight and weight gain of Tilapia fish (p <0.05).

As commonly observed, requirement estimates differ in the same species depending on the response variable used, as reported in tilapia, Oreochromis niloticus (Luis and Ronald 2020).So, when Hu et al. (2006) fedhybrid tilapia fed diets supplemented with 50,000 IU vitamin A kg^–1 present better weight gain. Therefore, the fluctuation in K-value may reflect the health condition of the fish attributed to feeding rate and protein and lipid contents.

The lower requirement of Tilapia to vitamin A may be due to its ability to utilize β-carotene to fulfill the dietary vitamin A requirements. The conversion ratio by weights of β-carotene to vitamin A was approximately 19:1(Hu et al., 2006).

Taking in consideration other fish species, sunshine bass fed diets supplemented with 509 – 40,516 μg vit A kg^–1 had no difference in weight gain (Hemre et al., 2004). Also, Atlantic halibut fed diets supplemented with 0-250 mg of retinal kg–1 had no differences in final weight (Moren et al., 2004).

5-Feed conversion (FCR):

Data concerning feed conversion of the experimental fish was illustrated in Table (8). At the second week, there was significant (P<0.05) difference in feed conversion between the fish group of T3 and control ones. Contrary, there were insignificant (P>0.05) variations in FCR between the fish group of T1 and T2 as compared with control group.While there were no significant (P>0.05) differences in FCR for all the fish groups and control ones at the fourth, sixth and eighth week. Meanwhile, the FCR of fish group fed 10 mg D₃/Kg diet (T3) decreased insignificantly (P>0.05) i.e. it is improved as compared with control group at the tenth week.But there were no significant differences in FCR between fish groups of T1 and T2 and control ones.

The obtained results concerning the effects of dietary supplementation of vitamin A and D₃ on feed conversion (FCR) of Nile tilapia are shown in Table (8).

The FCR value is closely related to the growth of tilapia. A low FCR value indicates better feed efficiency. The high and low feed conversion ratio is influenced by several factors, especially the quality, and amount of feed, fish species, fish size and water quality. Feed efficiency describes the ability of fish to utilize feed optimally (Winfree and Stickney 1981; Omasakiet al., 2017).Moreover,Kushayadiet al. (2020)found that the FCR values for O. niloticus ranged among 1.15 to 1.39 less than the range of 1.2 to 1.8 reported in O. niloticus.

Table 8: Average feed conversion (FCR) of O. niloticus fed different experimental diets.

Based on the obtained results in this study, the FCR value did not show significant differences (P>0.05) between fish group fed 20000 IU vitamin A (T1) and 40000 IU vitamin A (T2), but it decreased in fish group fed 10mgD3/kg(T3)as compared to T1,T2 and control ones.

Some studies showed thatdietary levels of vitamin A up to 5.400 IU kg^–1 did not influence feed consumption (Daniela et al.,2009). Saleh et al. (1995) also observed that Nile tilapia juveniles fed diets supplemented with 5,000 IU vitamin A kg^–1 presented better feed consumption rate and better feed conversion ratio than fish fed diets containing 0, 10,000 or 40,000 IU vitamin A kg–1.Moreover, Dawood and Koshio (2016) reported that the FCR valuefor tilapia did not affected significantly (P>0.05)with the usage of vitamin A.In the same trend, Guimarãeset al. (2014) reported that after two weeks of feeding, fish fed the vitamin A unsupplemented diet exhibited significantly lowest feed intake and feed efficiency ratio than those of other treatments. Mohamed et al. (2003) observed that Sunshine bass fed diets supplemented with 509 – 40,516 μg vit A kg^–1 had no difference in feed efficiency.

Contrary, Hu et al. (2006) reported that hybrid tilapia fed diets supplemented with 50,000 IU vitamin A kg^–1 present better feed conversion ratio (1.00). Also,Mohamed et al. (2003) observed that diets supplemented with 3,764 mg vitamin A kg^–1 for greasy grouper led to a better feed conversion ratio.

It is remarkably that increasing vitamin A supplementation higher than requirement level enhanced some nonspecific effects.

6- Hepato, gonado and spleeno – somatic indices:

The data of hepato, gonado and spleeno–somatic indicespresented in Table (9). The HSI of the fish group fed 10 mg vitamin D_3/ Kg diet(T3) increased significantly (P<0.05) as compared with control group. While, there were no significant (P>0.05) variations in HSI between the fish groups of T1 and T2 and control group. For spleenosomatic index, the SSI of the treated fish groups (T1, T2 and T3) decreased insignificantly (P>0.05) comparing to the control group.Otherwise,there were no significant differences in GSI between all treated fish groups and control ones.

The results presented in Table (9) revealed that the diet supplementation  with 20000 IU vitamin A or 40000IU vitamin A had insignificant( P>0.05) effect on HSI. While, the dietary incorporation of 10mg D₃/kg led to significant (P<0.05) increase in HSI.

The liver plays a major role in the metabolism, uptake, storage and release of vitamin A (Batres and Olson, 1987). Guimarãeset al. (2014) reported that dietary deficiency of vitamin A has been shown to cause liver damage and reduced liver size in the fish. So, they showed that O. niloticus fed vitamin A unsupplemented diet had significantly lower hepatosomatic index (HSI) relative to the groups fed vitamin A supplemented diets. Hu etal. (2006) referred these results to increasing of liver vitamin A retention with increasing dietary vitamin A. Also, a significant reduction of HSI was also demonstrated in common carp fed the vitamin A-deficient diet (Yang et al., 2008).

Table 9: Average hepato, spleeno and gonadosomatic indices ofO.niloticus fed different experimental diets.

While, In Japanese flounder, Hernandez et al. (2007), observed no significant differences in HSIamong fish fed different levels of dietary vitamin A, but lower values were recorded in fish fed the diet without supplementalvitamin A.

Salehet al.(1995)showed that in tilapia fish enlargement of liver and spleen coincided with vitamin A levels. Therefore, hemorrhagic, amorphous,granulomatous spleen; necrotic, granulomatous, amorphous liver were conspicuously found in fish receiving less than 1,200 IU vitamin A kg^–1 diet. Spleen severe conditions were also registered to a lesser extent in fish fed diets containing 1,800 - 2,400 IU vitamin A kg–1 diet.

Additionally, the gonado-somatic index increased insignificantly (P > 0.05) in T1, T2 and T3 as compared with that of the control group.

These results coincided with Salehet al.(1995) findings which showed the role of vitamin A on fish organs.

CONCLUSION

The results of this study indicated that the high levels(20000 and 40000)IU vitamin A and 10mgD₃ had insignificant effects on growth parameters (body weight, body weight gain, total length, length increment, condition factor), and food conversion(FCR) and body indices (HSI,SSI and GSI) of Nile tilapia(O.niloticus). In view of the results of the present study, the potential of using high levels of supplemental vitamin A and D₃ to improve growth parameters of Nile tilapia is not warranted. However, for future research it could be recommended more researches are needed to test lower levels of vitamin A and D ₃ in Nile tilapia(O. niloticus) feeds.

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