IMPACT OF SUPPLEMENTATION OF FIBROLYTIC ENZYME IN RUMINANTS IN NORTH AND CENTRAL INDIA

Dr. Ananth Krishnamurthy: Associate Product Manager, Kemin Industries
Dr. Tarjan Kaliaperumal: Senior Scientist, R&D, Kemin Industries
Dr Sudhir Singh: General Manager-Technical services, Kemin Industries

Abstract: The supplementation of enzymes in ruminant diets has been identified as a viable strategy to improve nutrient digestion and boost productivity. Enzymes play a vital role in the breakdown of complex fibers in the diet while stimulating the microbial population hence, synergizing fiber breakdown. This is noted to further impact volatile fatty acid production and energy availability to the animal, crucially impacting both milk yield and milk fat synthesis. The effect of exogenously supplemented enzymes in HF cows and Murrah buffaloes in the northern and central regions of India, respectively, were considered for this analysis. Briefly, the animals in these trials were divided into control and treatment groups, with the treatment groups supplemented with enzymes, apart from the regular concentrate and roughage feeds in both groups, over an average period of 21 days in cows and 27 days in buffaloes. Milk yield and Milk fat were monitored during the trial period for cows and milk yield was monitored in buffaloes. The results, on average, indicated an increment in both milk yield and milk fat in HF cows in Punjab by 8% and a 4% increment in milk yield in buffaloes in Madhya Pradesh. It can be concluded that exogenously supplemented enzymes in ruminant diets positively impact productivity by influencing fiber breakdown and nutrient utilization.

INTRODUCTION

India is currently one of the world’s leading producers and consumers of milk. Increasing demand and subsequent supply of milk are primarily driven by an anticipated increase in milk prices and demand in the export market. Other milk products like skimmed milk powder and reconstituted milk products further drive this demand for increasing milk production (DAHD, 2018). As a tropical country, India faces challenges related to increasing raw material prices, lower quantity and quality of feed and fodder sources, and sub-optimal productivity of cows and buffaloes. Over the years, animal nutritionists have recognized the importance of improving the quality of available feed through the application of physical, chemical, and biological methods The application of exogenous feed enzymes in monogastric nutrition is a well-established concept. While research on enzyme supplementation in ruminant diets had been initiated in the 1960s, progress had been sluggish due to a lack of understanding of the rumen function, variable results, and higher cost of production of enzymes. Latest developments in the field of industrial biotechnology enhanced understanding of rumen function and increasing studies of enzymes in ruminants have fueled the confidence of nutritionists to incorporate exogenous enzymes in ruminant feeds (Sujani & Serasinhe., 2015).

Feed breakdown in ruminants is primarily carried out by rumen microbes, which produce mainly 3 types of enzymes. Fibrolytic, proteolytic and amylolytic enzymes are produced by microbes that help in fiber and protein digestion. A major challenge is the sub-optimal digestibility of feeds and fodders. It is estimated that fiber digestion occurs only to a degree of 65-70% even in ideal conditions (Zhang and Lynd, 2004; Van Soest, 1994). Fiber is a major source of energy for ruminants, and its digestion, therefore, is greatly compromised. This limits the amount of energy available to the animal, especially during the transition and lactation stages resulting in sub-optimal productivity, higher loss of body condition after parturition, and predisposed to metabolic diseases.

Fiber digestion is mainly carried out by fibrolytic enzymes produced by rumen microbes. These include cellulases, xylanases, glucanases, pectinases and so on (McAllister and Wang, 2002). These enzymes break down the cell wall structures containing cellulose, hemicellulose, and pectins to release glucose, cellobiose, and other polysaccharides. While the rumen microbes manage to break down fibers, a large fraction remains undigested due to various factors. The digestibility of feeds, ruminal environment like pH, temperature, rate of feed passage, rumen microbial status, and stage of the animal during which the feed is presented play a vital role in determining the efficiency of feed and fiber digestion (Beauchemin et al., 2003, 2004).

To mitigate such high variability in feeds, their digestion, and dynamicity of rumen environment and microbial action, exogenous supplementation of feed enzymes have been identified as a trusted alternative to ensure optimal fiber digestion, while synergistically improving rumen microbial function and environment.

A key noteworthy aspect of exogenous enzymes is their stability in lower pH conditions. The supplementation of high-grain diets in ruminants predisposes the rumen to an acidic environment which impacts the population of fibrolytic microbes whose activity is pH dependent with peak activity within the neutral pH conditions. Exogenous enzymes have a lower optimum pH activity which makes them effective even under variable pH conditions (5-6.2 pH) (Russell and Wilson, 1996) (Beauchemin et al., 2003, 2004).

The impact of exogenous enzyme supplementation in cows and buffaloes was analyzed in these trials, especially in high milk-producing areas of India. A cocktail of enzymes, namely xylanases, cellulases, mannanases, glucanases and a specialized debranching enzyme complex, called xylanase potentiating factor (XPF) were supplemented to cows and buffaloes in the respective territories and their impact was analyzed.

OBJECTIVE

The objective of this study was to evaluate the effect of exogenous feed enzyme supplementation in Holstein Friesian cows in Punjab and Murrah buffaloes in Madhya Pradesh. Punjab and Madhya Pradesh are two of India’s highest milk-producing states contributing 6.7% and 8.5% of India’s milk production respectively (DAHD,2018). The effect of enzymes on milk yield and milk fat in HF cows and milk yield in Murrah buffaloes were considered for this study. The enzyme supplemented in this study was KEMZYME® One Advance, from Kemin Industries South Asia Pvt Ltd.

TRIAL DESIGN

Two trials were conducted for the evaluation of enzyme supplementation in cows and buffaloes.

The first trial was conducted in Holstein Friesian cows, in the early lactation stage in Punjab. An average of 8 animals in control and 8 animals in the treatment group were taken, with the treatment group supplemented with 5g of KEMZYME®. The trial duration was for a period of 21 days, with an average of 5 days as a pre-trial period. Both groups were fed with an average level of 10 kg concentrate feed, 1.6kg wheat straw, 23 kg corn silage, and 10kg green fodder. Milk yield and milk fat were documented daily.

The second trial was conducted on Murrah buffaloes in the early lactation stage in Madhya Pradesh. An average of 18 animals in control and 18 animals in treatment were taken, with the treatment group supplemented with 7g of KEMZYME®. The trial duration was for a period of 27 days, with no pretrial period. Both groups were fed with 6kg of straw and 8kg of concentrate feed. Milk yield was documented on a bi-weekly basis. It may be noteworthy that the trials were conducted in the peak summer season, between April and May, when the temperature is likely to be beyond 40˚ C.

RESULTS

Figure 1 represents the average milk yield of HF cows in Punjab, where an increment of 8% in milk yield was noticed, while Figure 2 represents the average increment in milk fat by 8% which was observed.

DISCUSSION

The usage of exogenous feed enzymes for fiber breakdown has been gaining acceptance steadily. This can be attributed to increased knowledge of enzyme action, less expensive cost of production, and greater understanding of rumen and rumen microbiome function (McAllister et al., 2003). The mechanism of action of feed enzymes can be broadly classified into four modes, the first being the direct hydrolysis or breakdown of fibers to release sugars. Secondly, the release of sugars creates a chemotactic attraction of microbes to the site of sugar release and increases their attachment to the fibers. This attachment is highly synergistic as the microbes themselves would produce fibrolytic enzymes which further degrade the fiber. Thirdly, this mechanism further stimulates the growth and multiplication of ruminal microbes. Fourthly, the increased microbial biomass due to exogenous enzymatic breakdown increases the supply of metabolizable protein to the intestine. The overall impact of exogenous feed enzymes can be noticed in the improved metabolic status of ruminants, higher feed digestion leading to better nutrient utilization, positive rumen microbial status, and enhanced productivity parameters in animals, mainly milk yield, milk fat and possibly milk protein (Kung, 2001) (Sheppy, 2001). Any inconsistency in the results is likely due to the type of enzyme prepared, synergy of enzyme activities, levels of enzyme applied and to what fraction of the diet, enzyme stability, mode of application and animal differences as well as whether the cows are in a negative energy balance and able to respond to increased available energy (Beauchemin, 2003).

The results obtained in our studies in cows are consistent with numerous in-vivo trials conducted (Lewis et al., 1999; Gado et al., 2009; Holtshausen et al., 2011). These studies reported an increase in milk production ranging from 5-16%, whereas we have reported an increase in milk production, on average by 8%. It is likely that enzyme supplementation in concentrate feeds would have improved the utilization of nutrients in the digestive tract and the rumen, along with an increase in the gain of net energy. The increase in milk fat, observed in our studies is also consistent with studies done by other workers (Yang et al., 1999) and (Mansour, 2009), who observed that milk fat increased after the application of fibrolytic enzymes. This increase has been attributed to the effect of enzymes on the production of fatty acids essential for fat synthesis, while also increasing the available energy to the ruminants (Babak and Akbar, 2012).

Buffaloes are well known for their ability to digest low-quality roughages. A combination of xylanases and cellulases was noted to have increased milk yield on numerous occasions as concluded by Azam et al., (2017), who had observed an increment in milk yield in Nili Ravi buffaloes by 12% and 17.7% when fibrolytic enzymes were given at 10g and 15g per day. Another study by Shelke et al., (2010) in Murrah buffaloes, showed an increment in milk yield by 12% when a combination of fibrolytic enzymes was supplemented at 1.5g/kg DM. there is a trend of increase in milk yield in buffaloes, which was consistent with our findings, where an increase in milk yield by 4% was noticed. A comparatively lower increment in our study could be attributed to the lower dosage supplemented in our studies, an average of 7g/animal as compared to 10-15g/animal supplemented in the studies discussed. It is likely that an increase in enzyme dose in buffaloes may have improved the milk yield linearly.

CONCLUSION

From the studies conducted in cows and buffaloes in northern and central India, respectively, it can be concluded that the combination of xylanases, cellulases, and debranching enzyme supplementation may have had a beneficial impact on cow’s milk and milk fat production while improving the buffalo milk production.

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