Abstract: An experiment was conducted for comparative study on the performance of commercial broiler chickens fed ration with DL-methionine or with herbal methionine. A-day old, 180 Ven Cobb broiler chicks were randomly divided into three experimental groups, comprising three replicates. Each replicate was consisted of 20 birds. The birds were fed basal diet without methionine supplementation (C), diet with DL-methionine at 1.2 kg ton-1 of feed (T1) and diet with herbal-methionine at 1.2 kg ton-1 of feed (T2). Superior performance (p<0.05) in body weight gain and Feed Conversion Ratio (FCR) were found in methionine supplemented group in either synthetic or herbal form. The cumulative feed and protein consumption were varied significantly (p<0.01) among the groups due to dietary treatments. Protein and energy utilization percentage was also varied significantly (p<0.01) among the groups. Liver protein, lipid and triglyceride varied (p<0.01) due to supplementation of DL-methionine or herbal methionine. Though methionine supplemented groups had little effect on meat quality but had supper effect on feather quality of broiler chicken. Statistical analysis revealed that cost benefit ratio was found significantly and economically viable in T1 and T2 groups than control. In terms of body weight gain, FCR, protein and energy utilization ability, feather quality, the superior performances were found in methionine (both form) supplemented group than control group where no methionine either synthetic or herbal form was supplemented form external source.
INTRODUCTION
Poultry nutrition has improved a lot for past few decades. In spite of advances made on the nutritional aspects, a lot many nutritional problems are still remaining unsolved and serve as a challenge to investigators in this field worldwide. Genetic potentiality of broiler chickens is increasing day-by-day; hence reassessment of nutrient requirements is essential to bridge the gap between the genetic improvement and nutritional requirements. One of the most important areas is amino acid nutrition. Of the essential amino acids required for poultry methionine is usually first limiting in diets based on maize and soybean meal (Fancher and Jensen, 1989). One cause of methionine deficiency is the fact that large amounts of vegetable protein supplements are now used in feeds, plus low levels of animal and fish proteins (North and Bell, 1990). It is more economical to add methionine than more soybean meal or other natural protein to meet the requirement.
Methionine, an indispensable amino acid, must be supplied in the diet of the chicken, as the poultry birds are unable to synthesize it in the amounts necessary to sustain life and growth. Methionine is required at higher level than normal level to comply with the increased tissue demands when bird is predisposed to fast growth along with high production performance. The increase in demand for cheap meat has given rise to the use of synthetic compounds in feed. Recently the safety of such practices has been questioned and their use is becoming restricted in many regions of the world. Therefore, there is great renewed interest in developing natural alternative supplements to maintain animal performance and well being. When more synthetic amino acids are used, not only the crude protein supply is reduced but excess of limiting amino acids are usually minimized. In a normal diet the supply of non-essential nitrogen arises from dietary non-essential amino acids plus any excess of essential amino acids. Limited supply of non-essential nitrogen is often quoted as a cause for poorer performance of birds fed low protein-amino acid fortified diets. The growth rate of birds is often inferior when regardless of amino acid balance, the ratio of crude protein: synthetic amino acid is much less than 16: 1 (Leeson and Summer, 2001). Methionine may act as a lipotropic agent through its role as an amino acid in balancing protein or through its role as a methyl donor and involvement in choline, betaine, folic acid and vitamin B12 metabolism (March and Biely, 1956; Chen et al., 1993). Methionine serves as an integral portion of body protein, is a precursor for cystine and an important source of dietary sulfur. S-adenosyl methionine is a potent donor of methyl groups, which contributes to the synthesis of many important substances including epinephrine, choline and creatine (Bender, 1975). Fancher and Jensen (1989) set methionine in the first position among amino acids limiting chicken growth.
Nature has provided natural plants with methionine in dipeptide and oligopeptide forms in readily digestible composition. When nature provided methionine to the plants for sustaining life and growth, it also concomitantly provided the enzymes required for conversion of methionine into L-isomer of active form (SAM) for its optimum utilization. Herbal methionine (HerboMethione®) as a source of Active Methionine is claimed to be effective in its optimum activity for proper protein accretion and other functions in poultry birds so that they can reach better growth and performance potential. In this perspective a study was conducted to evaluate the effects of herbal methionine in commercial broiler chicken in comparison with synthetic methionine.
MATERIALS AND METHODS
One hundred and eighty day-old, commercial broiler chicks (Ven Cobb) were randomly divided into three experimental groups, each of which comprised three replicates. Each replicate consisted of 20 birds. Groups were control (C) - Basal diet without methionine supplementation, treatment 1 (T1) - Diet with synthetic DL-methionine at 1.2 kg ton-1 of feed and treatment 2 (T2) - Diet with HerboMethione as a herbal-methionine at 1.2 kg ton-1 of feed. The rations were isonitrogenic in control and treatment groups and formulated according to BIS (1992). The research was carried out on June 2004-July 2004 at the department of Animal Nutrition, West Bengal University of Animal and Fishery Sciences, Kolkata, India.
Management
Both broiler starter and broiler finisher rations were offered to the birds
in mash form. Starter mash was fed from second day of experiment to 28th day
of experiment. After that finisher ration was provided up to the end of experiment.
Birds were maintained on a 24 h constant light schedule. Feed and water were
offered for consumption ad libitum. The brooding temperature was maintained
close to the requirement. Vaccination of birds was done time to time (Table
1).
Body Weight
Daily body weight of individual bird was recorded to evaluate the growth
rate. On the basis of this daily body weight, cumulative body weight (weekly)
of birds of each replicate was measured.
| Table 1: | Ingredients and chemical composition of starter and finisher diet |
| †: Composition of each kg trace mineral mixture : Cu, 15 g; Co, 02 g; Fe, 60 g; Zn, 80 g; Mn, 80 g; I, 02 g; Se, 0.3 g; Mo, 0.1 g, ‡: Each kg contains : Vitamin A 80 MIU; Vitamin D3 12 MIU; Vitamin E -70 g; Vitamin K3-8 g; Vitamin B1-6.4 g; Vitamin B2-40 g; Vitamin B6-12.8 g; Vitamin B12-160 mg; Nicotinic acid-80 g; Vitamin B5-115 g; Folic acid-4 g; Biotin-24 mg, ¶: Each kg contains: Cellulase-6,000,000 U; Xylanase-10,000,000 U; β-glucanase-700,000 U; α-amylase-700,000 U; Pectinase-70,000 U; Protease-3,000,000 U; Phytase-400,000 U, a: Assayed value, b: Calculated value | |
Feed Consumption
The feed consumption in each replicate was recorded daily by subtracting
the weight of residual feed from the total quantity offered. After that, cumulative
feed consumption was measured on cumulative basis for each replicate.
Feed Conversion Ratio
The weekly feed conversion ratio was calculated on cumulative basis for
each replicate.
Cumulative Energy and Protein Consumption
Cumulative energy and protein consumption were calculated from cumulative
feed consumption.
Energy and Protein Utilization
To evaluate the energy and protein utilization efficiency of birds, a 5
day metabolic trial was conducted starting from 38th day of experiment. At first
energy and protein value of the feed consumed by the birds were calculated.
After that faecal energy value by bomb calorimeter and protein value by standard
method of AOAC (1995) were estimated. Thereby, energy and protein utilization
percentage were calculated.
Meat Quality
At 42 days of age, 4 birds from each replicate were sacrificed as per standard
procedure of evaluation of carcass characteristics. Then the carcasses were
defeathered, eviscerated and evaluated for dressing, bleeding, thigh muscle,
breast muscle and abdominal fat percentage. Water holding capacity of meat samples
was determined (Offer and Knight, 1988). The pH of the finely minced meat was
also determined (Gillespie, 1960) by using digital pH meter (Systronics, model
335).
Liver Lipid, Liver Protein and Liver Triglyceride Concentration
Livers were collected from the birds by careful removal of gall bladder,
thoroughly washed in running tap water and immediately stored at -20°C in
individual sample bags until analyzed further. Liver protein was estimated according
to AOAC (1995). Total liver lipid was determined by the method of Folch et
al. (1957). Liver triglyceride was estimated as per the standard method
described by Fletcher (1968).
DNA and RNA Ratio of Liver
DNA and RNA of liver were estimated as per the standard method described
by Clark (1964) in Experimental Biochemistry.
Blood Collection
Collection of blood was done at 42nd day of the trial. So for doing this
10 birds from each replicate were randomly taken and approximately 5 mL of blood
was collected from the wing vein and kept in properly labeled tubes. By centrifuging
the whole blood plasma was collected separately in plasma vials.
Total Protein, Albumin, Globulin, AST and ALT
Total plasma protein in each sample was determined with the help of UV visible
Spectrophotometer as per the method described in diagnostic kit (Keller, 1991).
Plasma albumin in each sample was determined with the help of autoanalyzer,
Microlab 200 as per the method described in diagnostic kit (Tietz, 1994). The
globulin fraction in the plasma samples was calculated by subtractions of plasma
albumin from total plasma protein. The plasma AST and ALT were measured as per
the method suggested by Schlebusch et al. (1974) as described in diagnostic
Kit with the help of Microlab 200.
Cost Benefit Ratio
Cost benefit ratio was calculated. Cost of starter ration was Rs. 10.38,
10.55 and 10.53 for group C, T1 and T2, respectively.
Cost of finisher ration was Rs. 10.30, 10.47 and 10.52 for group C, T1
and T2, respectively. Fixed cost estimated for different groups with
the cost of chick (Rs. 15.00 chick-1) + Transportation cost (Rs.
5.00 chick-1) + Medicine and Vaccination (Rs. 2.00 bird-1)
+ Labour charge (Rs. 10.00 bird-1) + Losses due to mortality (Rs.
2.00, 3.00 and 1.50 per bird, respectively for C, T1 and T2+
Depreciation of equipments (Rs. 1.00 bird-1). So, fixed cost for
C, T1 and T2 group was Rs. 38.00, 39.00 and 38.50, respectively.
Birds were sold at the rate of Rs. 48.00 per kg gross weight.
Statistical Analysis
The data obtained in all the experiments were subjected to statistical analysis
by the software SPSS 10 (SPSS, 1997). Levels of significance were calculated
as per the standard method described by Duncan (1995) whenever any effect was
found significant.
RESULTS AND DISCUSSION
Performance
Cumulative body weight (Table 2) of experimental birds of
different ages except at 4th week of age showed significant variation among
different experimental groups due to dietary treatments. The live weight of
T2 was higher throughout the experimental period.
| Table 2: | Week wise effect of herbal or synthetic methionine on body weight changes, feed consumption and feed conversion ratio |
| Similar alphabets at superscript denote homogenous means due to Duncan’s test at 5% level of significance, *: p<0.05, **: p<0.01, NS: Non Significant | |
At the end of 6th week birds under T2 gained the highest live weight which was significantly (p<0.01) differed from others. Body weight of C and T1 at the end of 6 weeks was comparable. There was no significant (p>0.05) variation between C and T1 group in terms of body weight changes. The present findings indicated that supplementation of herbal-methionine (HerboMethione) at 1.2 kg ton-1 of feed showed better performance in terms of live weight gain compared to supplementation of DL-methionine at 1.2 kg ton-1 of feed. This finding is correlated with the findings of Wang et al. (2004) who reported significant response of birds to methionine supplementation in terms of weight gain in 21 days and 42 days. Bertram et al. (1991) also reported that the highest level of DL-methionine supplementation (0.15%) the growth was improved by 8.3% than the unsupplemented control group.
Statistical analysis revealed that cumulative feed consumption (Table 2) was varied significantly among the experimental group due to dietary treatments throughout the experimental period except 5th week. At the end of starter period feed intake were found to be varied significantly among the groups. At the end of finishing period total feed intake by control group showed significantly (p<0.01) higher value than other groups. This result was in close agreement with the finding of Garlich (1985) who reported that feed intake differed significantly due to methionine supplementation. Findings from cumulative feed intake indicated that supplementation of herbal methionine did not improve the feed intake compared to DL-methionine supplementation.
Supplementation of herbal methionine and DL-methionine significantly (p<0.01) improved feed conversion ration (Table 2) than control. Final Feed Conversion Ratio (FCR) at the end of sixth week was higher in T2 compared to C and T1. FCR of T1 significantly differed (p<0.01) from C but no significant difference between T1 and T2 was observed. This finding is correlated with the findings of Garlich (1985) and Bertram et al. (1991) who found that feed conversion was better when methionine was supplemented in the diet. A similar result was also described by Huyghebaert (1993), Schutte and Pack (1995) and Rostagno and Barbosa (1995). But Wang et al. (2004) were not agreed with above findings. So it can be concluded that the addition of Herbomethione at 1.2 kg ton-1 improved feed conversion ratio of commercial broiler birds, which was beneficial to the farmers and the FCR was comparable to DL-methionine.
Protein and Energy Consumption and Their Utilization
Though protein consumption (Table 3) in T2
and T1 group was lower than control group, but protein utilization
ability of T2 and T1 group was found significantly (p<0.01)
higher than control group. Statistical analysis revealed that energy utilization
capacity of birds differed significantly (p<0.01) among experimental groups
showing the highest value in T2 group followed by T1 and
C groups, respectively. From the above result, it can be concluded that supplementation
of Herboruthione in broiler ration elevated the efficiency of protein and energy
utilization of commercial broiler birds.
Liver and Plasma Biochemical Profiles
Liver protein and lipid (Table 4) were differed significantly
(p<0.01) among experimental groups. But there was no significant variation
in herbal methionine and DL-methionine supplemented group. Therefore, it can
be concluded that supplementation of HerboMethione in broiler rations elevate
protein concentration in liver and lower per cent liver lipid which have beneficial
effects to the birds. This finding indicates that supplementation of HerboMethione
facilitates efficient lipid metabolism in the liver and its transportation to
body tissues and consequently, it may reduce the incidence of fatty liver in
birds. Statistical analysis confirmed that liver triglyceride (Table
4) varied significantly (p<0.01) among various experimental groups showing
the least value (g kg-1) in T2 group followed by T1
and C groups, respectively. Though liver lipid concentration did not varied
significantly between T1 and T2 groups, but liver triglyceride
concentration varied significantly (p<0.01) between T1 and T2
groups. So supplementation of HerboMethione® in diets decreased
liver triglyceride markedly when compared to bird fed DL-methionine (synthetic)
supplemented diets.
| Table 3: | Effect of herbal or synthetic methionine on protein and energy consumption and their utilization |
| Similar alphabets at superscript denote homogenous means due to Duncan’s test at 5% level of significance, *: p<0.05, **: p<0.01, NS: Non Significant | |
| Table 4: | Effect of herbal or synthetic methionine on liver and plasma biochemical profiles |
| Similar alphabets at superscript denote homogenous means due to Duncan’s test at 5% level of significance, **: p<0.01, NS: Non Signifucant | |
Statistical analysis revealed that RNA and DNA ratio of liver (Table 4) also differed significantly (p<0.01) among various experimental groups showing the highest ratio in T2 group followed by T1 and C, respectively. There was also significant difference in RNA and DNA ratio between T1 and T2 groups. So supplementation of HerboMethione in diets increased RNA and DNA ratio significantly when compared to bird fed DL-methionine supplemented diets. Increased RNA and DNA ratio in liver due to supplementation of herbal-methionine in diets indicates increased carcass production with better meat quality.
Statistical analysis revealed that total plasma protein, albumin, aspartate amino transferase (AST) and alanine amino transferase (ALT) did not vary significantly among experimental groups due to dietary treatments. Total protein, albumin and globulin concentration in plasma were in the normal range throughout the experiment (Prabhakaran et al., 1996). The concentration of AST and ALT also was in normal range throughout the experimental period (Marjanovic et al., 1975).
Mortality
Birds were died mainly due to accidents (like falling of chicks from brooder
cages) and heat stoke. One chick of T1 group was died due to gout.
The least mortality (Table 5) was found to be in T2
group followed by C and T1 groups, respectively. However, on post
mortem examination of birds fed diet without methionine supplementation showed
moderate increase in liver size and also liver was pale. But birds fed HerboMethionine
at 1.2 kg ton-1 feed showed relatively decrease in liver size compared
to DL-methionine at 1.2 kg ton-1 feed.
Meat Quality and Feather Quality
Though dressing percentage did not differ significantly among various experimental
groups, but showing the highest value in T2 followed by T1
and C, respectively. Dressing percentage was found to be slightly higher in
HerboMethione supplemented groups than DL-methionine supplemented group. So
supplementation of HerboMethionine in diets increased dressing percentage slightly.
Abdominal fat and breast percentage did not also varied significantly due to
supplementation of herbal methionine or synthetic methionine. But the thigh
muscle percentage varied significantly (p<0.01) among various experimental
groups showing the highest value in T2 followed by T1
and C, respectively. These results were not agreed with the results of Ojano-Dirain
and Waldroup (2002) who observed significant improvement (p<0.05) in dressing
percentage and breast meat yield between the broilers fed NRC Methionine level
and those fed higher levels. Earlier studies reported that DL-methionine supplementation
decreased fat deposition (Huyghebaert et al., 1994; Jeroch and Pack,
1995; Schutte and Pack, 1995; Virtanen and Rosi, 1995) which was also found
in present study. It can be concluded that supplementation of HerboMethione
in diets increased deposition of meat in thigh muscles when compared to bird
fed DL-methionine supplemented diets.
| Table 5: | Effect of herbal or synthetic methionine on mortality meat and feather quality in commercial broilers |
| Similar alphabets at superscript denote homogenous means due to Duncan’s test at 5%level of significance, **: p<0.01, NS: Non Significant | |
| Table 6: | Effect of HerboMethione on cost benefit ratio in commercial broiler production |
| Similar alphabets at superscript denote homogenous means due to Duncan’s test at 5% level of significance, *: p<0.05, **: p<0.01, NS: Non Significant | |
pH of meat did not varied significantly within groups. Statistical analysis confirmed that Water-Holding Capacity (WHC) did not varied significantly due to dietary treatments.
Supplementation of HerboMethione® in broiler diets had very little effect on colour of feather. In this experiment it has been observed that colour of feather of birds of C group showed whitish colour with black spot that was not desirable from marketing point of view. Though white colour of feather was found to be in T1 and T2 groups. Supplementation of HerboMethione in broiler diets had no extra influence on rate of feathering and feather pecking in comparison to DL-synthetic methionine. The overall appearance or condition of feather of birds of T2 group was very good than control group and comparable to T1 group.
Cost Benefit Ratio
From the Table 6, it was clear that for meat production
the least money was expended in HerboMethione supplemented group. Statistical
analysis confirmed that the net return (Rs.) was significantly (p<0.01) varied
among various experimental groups showing the highest return in T2 group
(89.94) followed by C (84.53) and T1 (84.42) groups, respectively.
Net expenditure was varied slightly among experimental groups. This variation
occurred mainly due to variation in feed intake, variation in feed cost (per
kg) and variation in mortality in different groups. Statistical analysis revealed
that net profit was found to be significantly (p<0.01) highest in T2
group followed by T1 and C groups, respectively.
CONCLUSIONS
From the above results this was evident that for optimum growth and feed conversion HerboMethione (herbal methionine) can be used more efficiently than synthetic DL-methionine in broilers. HerboMethione had a significant effect on body weight gain with numerically lower FCR values compared to control birds without methionine supplementation. Thus, Supplementation of HerboMethione has a positive influence on the performance of broiler chickens, when compared to synthetic DL-methionine. For optimum molting, better feather quality and for reduction of feather pecking HerboMethione and DL-methionine can act efficiently in broilers. Herbomethione facilitates efficient lipid metabolism and transportation in liver and consequently reducing the incidences of fatty liver in broiler chickens. Thus, Supplementation of Herbomethione has a positive influence on the performance of broiler chickens, when compared to synthetic DL-methionine. So it can be concluded that 1.2 kg HerboMethione per ton feed can more efficiently replace 1.2 kg synthetic DL-methionine per ton feed with sustained and higher level of activity.