Vitamin C and electrolyte supplementation to support growth and meat yield of broilers in a hot humid environment

The study was aimed at determining the effects of Vitamin C and electrolyte on growth and meat yield of broilers in a hot humid environment. A total of 60 straight run day old Cobb 500 broilers were reared up to 35 days of age and fed ad libitum on a starter diet up to 12 days and thereafter, on a grower diet. The broilers were divided into 4 treatment groups. One group (15 broilers) without Vitamin C and electrolyte supplementation was considered as control. In other three groups were provided 135ppm Vitamin C, 1250ppm electrolyte and 135ppm Vitamin C + 1250ppm electrolyte in drinking water respectively as supplement. Feed intake, body weight, feed conversion and survivability were similar in broilers that received different levels of Vitamin C and electrolyte supplementation in drinking water. Feed cost per broiler and per kg broiler increased due to the addition of Vitamin C and electrolyte. Dressing yield, breast meat, total meat and wing meat were (P<0.05) higher in broilers that received Vitamin C in drinking water than those of control, electrolyte and Vitamin C + electrolyte supplemented groups. No differences (P>0.05) were found in breast: dark meat, thigh meat, drumstick meat and abdominal fat which could be attributed to either Vitamin C or electrolyte supplementation. It implies that deficiency of Vitamin C may be related to reduce meat yield of broilers in a hot humid environment. However, further experiment using several doses of Vitamin C with large number of broilers may be conducted to confirm the appropriate doses of supplementation.


Introduction
High temperature is a major limitation to growth and meat yield of broilers in tropical countries of the world (Howlider andRose, 1987 andArjona et al., 1988).Reduced feed intake, growth rate, feed conversion, survivability, dressing yield, breast meat and total meat and increased abdominal fat are the immediate consequences of rearing broilers in a hot humid environment (Geraert, 1998).Depleted performance and decreased profitability of broiler are aggravated when high temperature is associated with high relative humidity (Charles et al., 1978).Broiler with higher growth rate suffer more at elevated house temperature than that of slow growing broilers (Bohren et al., 1982).Summer mortality and reduced performance of the flock causes Tk. 1028 millions of loss per year to the poultry industry in Bangladesh (Islam et al., 2009).This situation demands an economic and efficient means to improve the thermo-tolerance of broilers in hot humid environment.Though vitamin C is not a dietary requirement, the requirement is increased at higher temperature.So, extra supplementations of vitamin C is needed to meet up additional requirements (Asaduzzaman, 2000).
Electrolyte supplementation has been reported to maintain acid base balance and thus improve performance of broiler rearing in a hot environment (Balnave and Gorman, 1993).Supplementation of Vitamin C and electrolyte in poultry diet is not normally practiced in Bangladesh.The essentialities of Vitamin C and electrolyte have been received attention of the nutritionists very recently.It is not quite known as to whether significant benefits or cost effective production could be derived if broiler diet are supplemented with Vitamin C and electrolyte during heat stress.The current study was aimed at to investigate the effects of Vitamin C and electrolyte supplementation on growth and meat yield of broilers in a hot humid environment.

Material and Methods
The experiment was conducted at Bangladesh Agricultural University poultry farm, with 60 Cobb 500 straight run day old broilers up to 35 days of age.The chicks were procured from the dealer of Kazi Farms Limited, at Shadeshi Bazar, Mymensingh.Commercial poultry feed Quality Feeds Limited, was brought from Sreepur, Gazipur.They were fed ad libitum on a basal starter diet (containing11% moisture, 245g/kg crude protein, 50g/kg fat, 40g/kg crude fibre, 14g/kg lysine, 6.5g/kg methionine, 12g/kg calcium, 7.5g/kg available phosphorus and 15.11 MJ metabolizable energy) up to 12 days of age.Thereafter, they were fed on a grower diet (containing 11% moisture, 240g/kg crude protein, 50g/kg fat, 40g/kg crude fibre, 14g/kg lysine, 6g/kg methionine, 12g/kg calcium, 7.5g/kg available phosphorus and 14.65 MJ metabolizable energy) on al libitum basis.Sixty day old broilers were divided into 4 treatment groups having 3 replications in each and 5 chicks per replication.One group of chicks was maintained as control, second group received 135ppm Vitamin C, third group received 1250ppm electrolyte and fourth group received 135ppm Vitamin C + 1250ppm electrolyte respectively as supplement.Four treatments were distributed in a Completely Randomized Design (CRD).Data were collected on body weight, feed consumption and survivability for each replication.Temperature and relative humidity were recorded every 4 hours.The minimum, maximum and mean of temperature were 24 0 C, 34 0 C and 29 0 C.While the minimum, maximum and mean of relative humidity were 70%, 96% and 83% throughout the experimental period.The body weight gains and feed conversion of broilers in each replication were calculated.At the end of the experiment, 1 male and 1 female broiler weighing average of each replication were selected and slaughtered.The birds were scalded, eviscerated and dissected to determine meat yield following the procedure of Jones (1984).Before statistical analysis, data on all meat yield parameters were converted into percentage of respective live weight.
Data were statistically analyzed in a Completely Randomized Design (CRD).Significant differences among treatments if any were identified using Least Significant Difference (Genstat 5 procedure, 1997).

Results and Discussion
Table 1 shows the results of growth performance of broiler.The data in this table indicate that the feed intake, live weight, feed conversion and survivability did not differ statistically (P>0.05)due to addition of either Vitamin C or electrolyte in drinking water.However, feed cost per broiler and feed cost per kg broiler increased (P<0.01) for the addition of Vitamin C and electrolyte.Additional feed cost /broiler and per kg broiler were 17.06, 10.40 and 27.80% and 20.92, 9.96 and 33.79% higher in Vitamin C, electrolyte and Vitamin C + electrolyte supplemented groups, respectively over the control Similar (P>0.05)feed intake recorded in broilers received different levels of Vitamin C and electrolyte contradict some previous findings (Vathana et al. 2002;Takahashi and Akiba, 2000;Tanveer et al. 2005;Saha et al. 2000 andBranton et al. 2004).They showed that supplementation of Vitamin C and electrolyte in drinking water or feed @ 500-3150 ppm and 300-350 meq/kg increased feed intake.However, the result was in agreement with Taweli and Kassab (1990).They showed that administration of VitaminC in feed did not change feed intake.It was assumed that supplementation of Vitamin C and electrolyte together in drinking water was not useful in respect of feed intake.There was no difference (P>0.05) in body weight gain among broilers received different levels of Vitamin C and electrolyte in drinking water (Table 1).This result was differed from those of Lohakare et al. 2005;Villar-Patino et al. 2002;Pirompud et al. 2005;Rezaei et al. 2004 andTanveer et al. 2005.Earlier workers observed that addition of Vitamin C and electrolyte in drinking water or feed @ 300-1500 ppm and @ 130-1000 meq/kg improved body weight.Doan (2000) and Bonsembinate et al. (2002) agreed with the result of the current study.They showed that addition of Vitamin C and electrolyte in drinking water or feed did not alter growth of broilers.No difference (P>0.05) was found in feed conversion for broilers receiving Vitamin C and/or electrolyte through drinking water (Table 1).This result was dissimilar with Mirsnamsollahi et al. 2003;Tanveer et al. 2005;Soleiman, andZulkifli 2010 andDraslarova et al. 2000;Raja and Qureshi, 2000.They concluded that addition of Vitamin C and electrolyte in drinking water or feed @150-500 ppm and 500 meq/kg improved feed conversion of broilers.Whereas, Villar-Patino et al. (2002) showed that Vitamin C in diet lowered feed conversion.Despite similar feed intake, live weight and feed conversion observed in groups received Vitamin C and electrolyte increased feed cost/broiler by 17.06, 10.40 and 27.80% in Vitamin C, electrolyte & Vitamin C + electrolyte supplemented groups respectively than that of control.Feed cost/kg broiler was increased by 20.92, 9.96 and 33.79% in Vitamin C, electrolyte and Vitamin C + electrolyte supplemented groups respectively than the control.Profit/broiler and per kg broiler were 1.5 and 0.5% higher in electrolyte supplement groups over the control.This may have been due to lower cost of electrolyte.Profit/broiler and per kg broiler were 4.7 & 6.6 and 1.6 & 2.09% lower in Vitamin C and Vitamin C + electrolyte supplement groups respectively over the control.Highest cost in Vitamin C receiving group might have resulted lower profitability.Dressing yield, total, breast and wing meat were higher in groups received Vitamin C in drinking water than those obtained on control, electrolyte and Vitamin C + electrolyte supplemented groups (Table 2).No significant difference (P>0.05) in the proportion of breast: dark meat, thigh meat, drumstick meat and abdominal fat were obtained for the administration of Vitamin C, electrolyte and Vitamin C + electrolyte.Higher dressing yield, total meat, breast and wing meat yield were observed (Table 2) in broilers receiving Vitamin C (135 ppm) coincide with Pisarski et al. 2003;Lohakare et al. 2004;Mbajiorgu et al. 2007 andBonsembinate et al. 2002.They showed that supplementation of Vitamin C through feed or water increased breast meat, dressing yield as well as total meat yield.Total meat yield was 14.08 and 3.88% higher in Vitamin C and electrolyte, but 0.54% lower in Vitamin C + electrolyte supplied groups over the control.Dressing yield was 6.71 and 3.33% higher in Vitamin C and electrolyte, but 1.55% lower in Vitamin C + electrolyte supplied groups than the control.Breast and wing meat yield were 16.09 and 8.34% higher in Vitamin C supplied groups over control.In Vitamin C receiving groups, females had 0.8 and 0.9% higher wing and total meat yield than that of males.On the other hand, wing and total meat yield were 0.42 and 4.24% higher in males received electrolyte.Drumstick bone yield was 1.8 and 1.7% higher in the Vitamin C and electrolyte consuming groups respectively.From the apparent results, it was concluded that Vitamin C and electrolyte sometimes may not be useful in improving growth performance.The data imply that some improvement in meat yield of broiler may be obtained for the supplementation of Vitamin C in drinking water.In this current study, broilers were sold alive.Therefore, quantification of increased meat yield was not possible.So, further investigation is needed by selling dressed broiler instead of alive.