Modulation of Performance Index, Glucose and Cholesterol Level in Broiler Chickens Fed Diets Containing Different Supplements

Poultry production in India has taken a quantum leap in the last six decades, emerging from an entirely unorganized and unscientific farming practice to a commercial production system with state-of-the-art technological interventions (Singh et al., 2017).
       
Corn and soybean meal are two major ingredients in commercial poultry diets in many parts of the world which contain a lower concentration of antinutritive high molecular weight-soluble nonstarch polysaccharides (NSP) that can impede normal digestion and absorption processes of nutrients including carbohydrates and proteins in the digestive tract by Govil et al., (2017). About 400-450 kcal of energy per kg of diet is not digested when birds are fed a typical corn-soy ration by Cowieson (2010).
       
The use of organic mineral mixtures improves performance, activates immune stimulation, optimizes minerals absorption and utilization and improves oxidative status in broiler chicks (Ravindran 2013).
       
Probiotic (Microguard) on administration passes through stomach reaches intestine where it colonizes occupying the intestinal villi and prevents pathogens from attaching to the intestine and at the same time favors the growth of favorable and essential microflora in the gut. They also produce substances like bacteriocins and local acting antibiotics that are antagonistic to pathogens. It also secretes enzymes like protease, amylase and lipase along with other nutrients and supplements which can be used by the lactic acid-producing and other useful bacteria to multiply rapidly and to sustain them for a longer time in the intestine. Further prevents clostridial and salmonella infections and reinforces the integrity of the gut wall and stimulates intestinal immunity-enhancing production of secretory antibodies.The use of exogenous feed specific enzymes (Brozyme) breaks down NSPs in feed ensuring more nutrient bioavailability and reduces the viscosity of the gut caused by NSPs–improves intestinal absorption of nutrients. Prevent gut pathogens to ensure gut health (Narasimha et al., 2016). Superior quality lean, tender, juicier, tastier and healthier meat with less abdominal fat.
       
The non-ionic emulsifier (Lipigon) promotes performance and reducing the nutrition density of feces. It aids fat-soluble vitamin absorption, increases Energy: Protein ratio, retains moisture of feed and maintains its nutritive value and keeps liver free from fat deposits, minimizes abdominal fat.
       
The trend of the non-vegetarian population in the globe is changing towards poultry meat consumption from red meat. Cholesterol content of poultry meat and products has become a primary area of consumer concern due to increased awareness of higher dietary cholesterol intake and incidence of obesity and hypercholesterolemia in human beings (Kaushal et al., 2018).
       
Consequent on the ban of the sub-therapeutic use of antibiotics as growth promoters in poultry feeds due to their undesirable effects such as the residues in meat products and development of antibiotic-resistant bacteria populations, research efforts in organic mineral mixtures, probiotics, enzyme and emulsifier supplementation has gained much attention to improving meat and egg production.
       
Hence, the present study was undertaken to assess the effect of various feed supplements and their combinations on the performance index, glucose and serum cholesterol of broiler chicken.

Experimental birds and dietary treatments
 
The present study was undertaken at the Instructional Poultry Farm (IPF) Nagla of Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, U.S. Nagar from 25^th August to 5^th October 2017. The place is located between 28°53' 23'' to 30°27' 50''N and 77°34' 27'' to 81°02' 22'' E at 243.84 m MSL (mean sea level) in the Tarai region of Uttarakhand State (India). The climate is humid subtropical. Winters are very severe and summers are hot and humid. Temperatures may rise to a maximum of 43°C in the summer and fall to a minimum of 2°C in the winter. Relative humidity ranges between 15 to 95% (Singh et al., 2015).
       
A total of 252, day-old commercial broiler chicks (VenCobb⁴⁰⁰) were procured for experimenting. All the chicks were individually weighed and randomly allotted to seven different groups each with three replicates of 12 chicks. The average body weight of chicks was similar for all the treatment groups. The study was conducted for 6 weeks under standard management conditions. Feed and water were provided ad libitum. The detail of experimental diets is given in Table 1.
 

       
The performance index (PI) was calculated as per the formula proposed by Bird (1955). 
 
Glucose and cholesterol analysis
 
At the end of three weeks of age 2 ml blood samples were taken from the wing vein of 6 fasting broilers per treatment group. Serum was obtained by centrifugation of blood at 3000 rpm for 10 min and then it was frozen at -20°C for future analysis. The glucose, total cholesterol, triglycerides, LDL and HDL was estimated spectrophotometrically (Span Diagnostics Ltd (R), Surat, India).
 
Statistical analysis
 
All data about various parameters were analysed statistically by running ANOVAs using SPSS 19 software. Significant mean differences between the treatments were determined at a 5% significance level (P<0.05) using Duncan’s Multiple Range Test (DMRT) as modified by Kramer (1957).

Performance index (PI)
 
Mean performance index at different intervals in different experimental groups are given in Table 2. During both phases (starter and finisher) the performance index of broilers increased significantly in all the treated groups as compared to the control group. It decreased significantly in the T6 group. The results of the study revealed that the addition of organic mineral mixtures, probiotics, enzymes, emulsifier and liver stimulants alone or in combination were found to increase performance index significantly. The reduction of 3% energy in group T6 led to significant depression in the performance index by 9.59%.
 

 
Cholesterol and glucose contents
 
Mean cholesterol and glucose contents at 21^st day in different experimental groups were given in Table 3. Total cholesterol values were significantly (P<0.05) decrease in T₂, T₃, T₄ and T₅ groups than T₀ group. The maximum cholesterol value (114.94 ± 0.27mg/dl) was found in the T0 group. Maximum HDL- cholesterol value of 59.81 ± 0.05 mg/dl was found in broilers of group T₄ followed by T₃ (59.64 ± 0.02), T₂ (59.30 ± 0.02), T₁ (59.21 ± 0.15), T₆ (58.47 ± 0.07) and T₀ (58.21± 0.07). HDL- cholesterol values in T₃, T₄ and T₅ groups were significantly (P<0.05) higher than the T₀ group. Minimum LDL-cholesterol value 43.10 ± 0.03 mg/dl was found in broilers of T₄ group followed by T₃ (43.77 ± 0.33), T₂ (44.62 ± 0.05), T₁ (44.94 ± 0.14), T₆ (45.99 ± 0.20) and T₀ (46.37 ± 0.02). LDL- cholesterol values were significantly (P<0.05) decrease in the broilers of feed supplemented groups in comparison to control except T₆. Maximum LDL-cholesterol value (46.37 ± 0.02 mg/dl) was observed in broilers of the T₀ group. Triglyceride’s values were significantly (P<0.05) decrease in the broilers of feed supplemented groups in comparison to control except T6. Maximum triglycerides value (46.17 ± 0.22 mg/ dl) was found in the broilers of the control T₀ group. Glucose values were significantly (P<0.05) decrease in T₃ and T₄ groups than the T₀ group.
 

       
These results regarding better performance index in enzymes (multicarbohydrases) supplemented group is also supported by Jose et al., (2009) and Govil et al., (2017). Kaushal et al., (2018), who noted that there was significantly (P<0.05) higher performance index of broilers fed the diet supplemented with enzymes and probiotics. Thorat et al., (2015) reported significant (P<0.05) improvement in the performance index of broilers fed the diet supplemented with prebiotics, probiotics and multi-enzymes. The predominant mechanism involved in the improved performance index is the pivotal role played by supplement break down NSPs in feed ensuring more nutrient bioavailability and reduces the viscosity of the gut caused by NSPs - improves intestinal absorption of nutrients. Prevent gut pathogens to ensure gut health. 
       
Similar to the findings of the present studies, Aluwong et al., (2013) and Chaudhary et al., (2017) noted significantly (P<0.05) reduced serum cholesterol and glucose values in broilers fed the diet supplemented with probiotics. Paryad and Mahmoudi (2008) found a significant (P<0.05) increase in serum HDL-cholesterol in broilers fed the diet supplemented with probiotics. Abdel-Fattah et al., (2008) found a significant (P<0.05) decrease in LDL-cholesterol of broilers fed the diet supplemented with probiotics. Saleh (2014) noted a significant (P<0.05) decrease in triglycerides of broilers fed the diet supplemented with probiotics. Devrim et al., (2010) found a significant (P<0.05) decrease in cholesterol of broilers fed the diet supplemented with organic minerals. Kaushal et al., (2018) noted a significant (P<0.05) decrease in serum total cholesterol, LDL- cholesterol, Triglyceride and significant (P<0.05) increase in HDL- cholesterol in broilers fed the diet supplemented with enzymes and probiotics.
       
In contrast, Shehab et al., (2012) found non-significant (P>0.05) differences in serum glucose and triglycerides of broilers fed the diet supplemented with enzymes.
       
It has been found that lactic acid bacteria reduce the cholesterol by assimilating endogenous or exogenous originated cholesterol in the intestinal tract and reduces the expression levels of Niemann-Pick C1-Like 1 (NPC1LI) a protein, expressed on the surface of enterocytes, which reduces the cholesterol absorption (Jia et al., 2011). Lactic acid bacteria produce bile salt hydrolase, an enzyme that is responsible for deconjugation of bile salts and it helps to excrete more bile acids in the feces. Thus it is possible to produce lean and healthier meat by using these supplements without hampering any physiological function.

The results of the present investigation revealed that dietary inclusion to a certain extent by manipulating diets reduced bad cholesterol, triglycerides and improved overall performance, increased good cholesterol to produce lean meat. The predominant mechanism involved in the improved performance index is the pivotal role played by different supplements which resulted in better nutrient absorption and is thus responsible for better performance.

Authors are thankful to the Director of the Experiment Station, G.B. Pant University of Agriculture and Technology, Pantnagar and the Dean of the College of Veterinary and Animal Sciences, Pantnagar for providing necessary facilities to experiment.