Studies on Use of Heat Treated Rock Phosphate Instead of Dicalcium Phosphate on Broiler Performance

An experiment was conducted using ninety-six, day old broiler chicks to study the effect of inclusion of heat-treated rock phosphate (HTRP) instead of dicalcium phosphate (DCP) on performance of broilers. Total four diets were tested. Control diet (T1) was prepared using maize 54.08 %, soybean meal 25.73 %, deoiled rice polish 9.19 %, fishmeal 8.00 %, mineral mixture (MM) 3.0 % and vitamin supplements. All the diets were isonitrogenous and isocaloric (22% CP and 2800 kcal ME/kg).

In T1, DCP was exclusively used as phosphorus supplement. While, in other three diets, DCP was replaced using HTRP @ 60, 80 and 100% (T2, T3, and T4). Inclusion of HTRP significantly increased the weight gain of broilers. Maximum gain was observed in broilers assigned T3 diet. Conversely, significant (P
Increase in the level of HTRP also reduced the feed intake significantly. As a result of which there was significant improvement in FER as well as PI in broilers with HTRP diets. There was also reduction in the cost of feeding and increase in the net return over feed cost due to incorporation of HTRP. Maximum net return over feed cost was noted in broilers assigned T3 diet. Hence, it was concluded that 80% HTRP can be incorporated instead of DCP in broiler diets economically.


INTRODUCTION

In broiler farming, feed accounts to about 65-70 % of total cost of production.

Beside cereals and protein supplements, next important input in broiler ration is mineral mixture. Phosphorus is a critical and expensive mineral used for preparing mineral mixture. Dicalcium phosphate (DCP) is used traditionally as phosphorus supplement in poultry diet.

However, due I to high demand and scarce availability, its cost is steeply increasing. Therefore, to reduce the cost of mineral mixture, it has become imperative to use alternate and economical phosphorus supplements.

One of the alternates is rock phosphate (RP), which is available in plenty at much lower cost. But on account of high level of fluorine in it10, its use is limited. To reduce the fluorine content of rock phosphate usually it is heat-treated. The heat-treated rock phosphate (HTRP) also contains fluorine but at much lower level than RP.

Therefore, present study was planned to see the utilization of heat-treated rock phosphate instead of DCP in broilers.


MATERIALS AND METHODS

The experiment was conducted using ninety-six, day old broilers chicks randomly allotted to 12 replicates. Total four diets were used in the study. All the diets were iso-nitrogenous and iso-caloric containing 22% CP and 2800 kcal ME/kg as per BIS³.

Feed ingredients used for diet formulation were maize, soybean meal, fish meal, deoiled rice polish, minerals and vitamins supplements. The ingredients were analysed for proximate constituents, energy, calcium and phosphorus content. Control diet was formulated using maize, 54.08 %, soybean meal, 25.73 %, DORP, 9.19 %, fish meal, 8.00 %, mineral mixture (MM), 3.0 % and vitamin supplements.

All the diets were same except the change in phosphorus supplement. Mineral mixture as reported in the Iiterature⁶ was used @ 3% in control diet. Diet I had only DCP as phosphorus supplement. Whereas, in other diets, DCP was replaced using HTRP @ 60, 80 and 100% (T2, T3, and T4). The fluorine content of HTRP was only 1.81 %. Each diet was randomly allotted to three replicates of 8 chicks each.


The experiment was conducted for a period of 6 weeks. During the experiment, weekly body weight, feed intake and left over feed was recorded and weight gain and feed efficiency ratio (FER) was calculated. Feed samples were analyzed for proximate constituents¹. While calcium and phosphorus contents were estimated by titrimetric method⁹. The energy content of the samples was estimated using titrimetric method⁵.

The performance of birds was measured in terms of weight gain, feed intake, feed efficiency ratio, performance index and economics of feeding. The performance index (PI) was calculated as detailed by Bird². The data obtained during the study were analysed⁷ and significance between the treatments were tested using Duncan's multiple range test⁴.


RESULTS AND DISCUSSION

The performance of broilers in terms of body weight gain, feed intake, FER and PI for 0-4 and 4-6 weeks is presented in Table 1 and 2 while including cost of feeding as well as net return over feed cost for 0-6 weeks is presented in Table 3.


Table 1. Performance of broilers on MM containing HTRP instead of DCP (0-4 week)





Increase in HTRP above 60% reduced the weight gain significantly. Among HTRP groups, minimum weight was attained by those receiving D4 diet.

Feed intake also increased due to incorporation of HTRP. Maximum intake recorded in broilers assigned T3 diet was comparable to those allotted T2 diet. While, minimum feed intake was registered in broilers offered T4 diet. Conversely, FER was maximum and significantly higher in broilers assigned T4 diet. FER of broilers assigned T2 diet was although bit lower but statistically comparable to those assigned T4 diet. Minimum FER was registered in broilers assigned T1 diet.

The PI was maximum and significantly (P During 4-6 weeks (Table 2), increase in the level of HTRP also increased the weight gain significantly. But complete replacement of DCP reduced it significantly (P
Minimum feed intake was noted in broilers assigned T4 diet. FER improved significantly (P

Table 2. Performance of broilers on MM containing HTRP instead of DCP (4-6 weeks)





The cumulative performance for 0-6 weeks (Table 3) also revealed that inclusion of HTRP instead of DCP up to 80% level, increased the weight gain significantly.

However, complete replacement of DCP reduced it significantly.

Studies revealed that inclusion of HTRP instead of DCP increased the weight gains of broilers significantly, however, it was true only up to inclusion of 80% HTRP. Complete replacement of DCP led to significant (P
As it was heat treated rock phosphate, it has low levels of fluorine (1.81%) and probably phosphorus was more available hence it improved the weight gain of broilers. The amount of fluorine ranged from 79.5 ppm in D2, 106.0 ppm in D3 and 132.5 ppm in D4. While the maximum and safe dietary level of fluorine in broilers is 300 ppm⁸. Thus, in all the groups fluorine level was within the tolerable limit.

Feed intake reduced due to inclusion of HTRP. It was minimum and significantly lower in broilers assigned T4 diet. As a result of it, FER improved significantly in HTRP groups but among these groups, differences were not significant (P > 0.05). As like FER, PI also improved significantly due to use of HTRP. On account of higher weight gain and lower feed intake besides lower cost of HTRP, replacement of DCP led to significant reduction in the feeding cost of broilers.

However, among HTRP groups (T2, T3 and T 4) differences were non significant. The net return over feed cost also increased due to use of HTRP. It was higher and statistically similar in groups assigned T2 and T3 diets containing 60% and 80% HTRP instead of DCP. Hence, it was concluded that up to 80%, HTRP can be used instead of DCP in the mineral mixture of broilers economically.


Table 3: Performance of broilers on MM containing HTRP instead of DCP (0- 6week).






REFERENCES

1. A.O.A.C. 1990. Association of official analytical chemist. Official Methods of Analysis, Washington, D.C.

2. Bird, H.R. 1955. Performance index of growing chickens. Poult. Sci., 34: 1163- 1164.

3. B.I.S. 1992. Bureau of Indian Standards. Nutrient requirement for poultry. First revision. Manak Bhavan, 9, Babadur Shah Zafar Marg, New Delhi, India.

4. Duncan, D.B. 1955. Multiple range and multiple F tests. Biometrics, 11: 1-42.

5. Oshea, J. and Maguire, M.I. 1962. Determination of calorific value of feed stuffs by chromic acid oxidation. J. Agri. Sci., 13: 530-534.

6. Singhal, P.K. and Baghel, R.P.S. 2003. Perfonnance and economical evaluation of mineral mixture in broilers. Indian J. Anim. Nutr., 20: 193-197.

7. Steel, R.G.D. and Tome, J .H. 1984. Principles and procedures of statistics, McGraw Hill International Book Co., 2nd edn.

8. Suttie, J., Simon,G. and Miles, R.D. 1982. Effect of dietary fluoride on food intake and plasma fluoride concentration. Poult. Sci., 61: 1033-1037.

9. Talpatra, J.K., Ray, S.C. and Sen, K.C. 1940. Estimation of phosphorus, chlorine, calcium, magnesium, sodium and potassium in feed stuffs. Indian J. Vet. Sci., 10:243.

10.Underwood, E.J. and Suttle, N.F. 1999. The mineral nutrition of livestock. 3rd edn. CABI Publishing, USA.


Authors: A. THOMAS, C. KAWATRA, R.P.S. BAGHEL and S. NAYAK
Department of Animal Nutrition - College of Veterinary Science and Animal Husbandry, Jabalpur- 482001,
M.P. (INDIA)