(Paper ini memenangkan juara II Lomba penulisan artilkel ilmiah pada Young Scientist Award oleh Alltech di tingkat asia pasific)
Department of Animal Nutrition and Feed Technology, Faculty of Animal Sciences,
Bogor Agricultural University (IPB).
Jl. Agatis Kampus IPB Darmaga, Bogor 16680
This paper describe the effect of fibrozyme supplementation on intake and digestion of hemicelluloses and cellulose in ruminant’s tract. Basically, rumen as the biggest compartement stomach does not product cellulase enzyme, but the enzyme produce by rumen microbial. Microbial activity on fiber digestion depends on kind and quality of feed ingredient, rumen condition and species. Supplementation of cellulose enzymes for ruminants had been reported improve the digesbility of fiber. Its affected on increasing of body gain and feed efficiency. Furthermore, fibrozyme as main product from altech complex enzymes which has xylanolitic and cellulolytic activity also positively affected on animal performance. The research reported that forage based basal diet containing fibrolytic enzyme supplementation increased final weight, average daily gain and dry matter intake, also VFA production and N retention. However, the supplementation of fibrozyme into high concentrate diet tended not effect on dry matter intake and animal growth. Generally, enzyme supplementation enhances fibrolytic activity in ruminal. Fibrozyme supplementation could improve fiber utilization in digestive tract of ruminant by enhance fibrolytic and its increased animal growth and more effectively impact on ruminant performance consumed feedstuff containing high fiber.
Feed digestion is process for breakdown components of feed from complex components into simple’s components. This process occurs largely through the catabolic action of enzymes. Rate of digestion depend on enzyme activity, concentration and exposure rate of substrate to the enzymatic process. Material component of feed ingredient which digested is carbohydrates, proteins, lipids minerals and vitamins. Water is not digested but directly to be absorpt. Carbohydrates are major components of
feed for herbivore animals (ruminants). The diet or animal’s feed in particularly consists of plants, or by product and waste product from agriculture. Mostly, this material contain high undegradable fiber such as cellulose, hemicellulose and lignin. Plants cell wall comprises on average 23% lignin, 40% cellulose and 23% hemicellulose by dry matter basis (Coughlan & Hazlewood, 1993). Xylans constitute the main polymeric component of hemicellulose, being present in the cell walls of all land plants, particularly in tissues that have undergone secondary thickening, where they are known to have important structural functions. Xylans are also present to some extent in the primary walls of growing cells, seeds and bulbs of certain plants species, as reserve polysaccharides. The structure of xylans are complex heteropolysacarides based on a backbone structure of β-linked xylopyranose residues (Coughlan et al., 1994). The β-1,3-linked are found only in marine algae, where in certain species, they from highly crystalline fibrillar structure in the absence of cellulose. Mixed-link β-1,3- and β-1,4-xylans are found in certain sea-weeds such as Palmaria palmata. Ruminant use fiber as energy source in their diet. Fiber degradation in ruminant done by rumen microbial. In contrast, the simple stomach can not use the fiber as energy source because they do not have rumen microbial. In the rumen, anaerobic bacterial, protozoa, and fungi have contributing on fiber degradation. Mostly, the bacteria appear to be the dominant fiber digesting group. Digestibility of plants substrate depends on the season harvest and phenolic component (Benner & Akin, 1988). Simple stomach like pigs and poultry do not have endogenous enzyme that capable to digest fiber, the digestibility achieved by chemical and mechanical (acid in the stomach in pigs and grit in chickens). The limiting factor of fiber digesbility in ruminant is anti-nutritive such as saponin and tanin. Digestibility depends on animal species, , chemical structure, and their diet quantity (Kocher & Choct, 2000).
Fiber in Ruminant’s Feed
Fiber is part of cell wall material which consist mainly by cellulose, hemicellulose and lignin. Cellulose is the major source of glucose, and hemicellulose provides xylose, mannans, and galactose. Fiber is importance components in ruminal diet, its to maintain normal ruminal fermentation and may be to prevent post-calving diseases (Mc Donald et al, 2002; NRC, 1988).
The amounts of fiber to be included in the diet of dairy cattle is influenced by body condition and level of production, type of fiber, particle size and size distribution of the fiber, total intake and bulk density, buffering capacity of forage and frequency of feeding. Generally, fiber should be fed as hay minimum of 1,5 percent of live weight (NRC, 1988).
Mostly, tropical grasses have low quality than sub-tropical grasses. The tropical grasses containt high cellulose and hemicellulose. Enzyme supplementation needs to increase utilization of fiber in their diet. Supplementation of fibrolytic enzyme in the diet increase ruminal fibrolytic capacity which making efficiency of fiber utilization.
Exactly, ruminants do not produce fibrolytic enzymes themselves, but it’s depending on relationship with microorganism in the ruminal tract for digestion plant cell walls. Fiber contains hemicellulose, cellulose and lignin which a rigidly component and undegradable in digestive tract. These fraction are collectively termed neutral detergent fiber (NDF). Digestion of cellulose is limited by this hemicellulose-lignin linkage. Hemi-cellulose comprise of pentose polymer known as xylan. It is hydrolysis by fibrolytic complex enzyme. Hemicellulose and cellulose can be breakdown into simple sugar, but lignin is undegradable. Anaerobic fungi are important in lignocellulose’s degradation in the rumen and its have contribute in the utilization of hemicellulose. Anaerobic fungi colonized by bacterial and protozoa to degradation the fiber (Trinci et al., 1987) Fiber digestion affected by supplemental fat, ionophores, antibiotics and lower ruminal pH.
1. Supplemental Fat
Lipids contains by unsaturated fatty acid. This fraction can be as inhibitor ruminal cellulolytic microbes (Zinn & Ware, 2002). Fat Supplemental has toxic effect on ruminal fibrolytic organism particularly protozoa (McDonald et al., 2002).
2. Ionophores supplementation
Ionophore is hydrolyzed components that have negative effect in ruminal microbes. The reaction by diffusion methods, ionophores is liquid that can entry in microbes cell and then population of ruminal microbial decreased by ionophores reaction. They act as lipid-soluble weak acids and provide a pathway of the flow of H+ across the inner mitochondrial membranes (Calbiochem, 2006).
Cellulose digestion is inhibited by tetracycline. Addition antibiotics in the diet has decrease total tract fiber digestion in ruminant. It is caused that the antibiotic contains by toxic substances for ruminal microbes.
4. Lower ruminal pH
To decrease ruminal pH will be done by increasing the level of carbohydrate intake diet, increasing level of feed intake and increasing the extent of grain.
Refers to Figure 1, show that product from microbial fermentation is volatile fatty acids, microbial cells and gasses methane and carbon dioxide. The acid product by fermentation is lactate acid that capable of reduce the pH of rumen. Feed additive can stimulate of fiber fermentation and increase of fiber utilization as energy source.
Factor that influence rate of ruminants fiber digestion is the accessibility of substrate to the fibrolytic process, particularly the physical chemical interaction of cellulose, hemicellulose and lignin. Characteristic of fiber source influenced by stage of maturity, storage time post harvest, preservation and processing. The rate of ruminal fiber degradation will be influenced by ruminal microbes.
Ruminal microbes have been production enzyme to break down fiber component to the simple sugar as energy source. Increasing fiber proportion in the diet followed by increasing enzyme treatment. It’s caused to help microbe’s action (Figure 1).
Climate is one of factor influence the quality of fiber. Indirectly, these factor influence of performance. The gain of cattle on tropical is usually lower than subtropical cattle. The main factor controlling the gain of cattle is the quantity of net energy (NE) absorbed each day. Three factor control the intake of net energy, the quantities of feed energy eaten (I), proportion of each unit of feed that digest (D), and efficiency of utilization the product of digestion (E). The pattern is:
NE = I x D x E
Thus, will depend on the chemical and physical composition of the grasses which in turn is related to soil condition, climate, species of grass, stage of growth and the part of the plant being eaten. The stem contain fiber more than leaf (Morley, 1981).
Tropical grasses generally contain less protein than temperate grasses. Legumes have much higher protein content than grasses. To increase protein deficiency from the grasses is addition legume in the diet (Mc Donald et al., 1991).
Generally, the tropical grasses have a lower voluntary intake and dry matter digestibility than temperate grasses due to a higher fiber content associated with the climate in which they are grown. Improvements the nutrition of tropical grasses will be use of suitable adapted legume supplements protein deficient.
The ruminants can utilize the major part of bulky, fibrous material only via microbes. Voluntary intake of ration rich in forage is generally restricted by the limited capacity of the digestive tract, particularly in the reticule-rumen. Disappearances of digesta from the reticule-rumen is possible either by microbial degradation and absorption of end product or by passage to the lower digestive tract of undigested residues, after sufficient reduction of particle size of microbial mass. In addition, thus factor limiting reduction of particle size or microbial degradation will generally reduce the voluntary feed intake. For maximum feed intake, the rate of disappearance of digesta from the rumen has to be optimized. Important factor in this respect are feed particle size and rate of degradation in the rumen (Haresign & Cole, 1988).
There are three trial to known the effect of fibrolytic enzyme supplementation which different variable each other. This experiment not only treat in differ variable but also in differ level of enzyme supplementation. From this experiment we know the best level enzyme supplementation for cattle.
The first trial (Zinn & Salinas, 1999) involved 96 crossbreed stress calves in a 64 day growing. Treatments consist of a steam flaked corn based growing diet that containing 22% forage with 0 or 15 g/hd/d fibrozyme supplementation. Feeding method is ad libitum that given twice a day. The result showed that fibrolytic enzyme supplementation increasing final weight (3%, P<0.10), average daily gain (ADG) (6%, P=0.13) and dry matter intake (4.5%, P<0.05). Enzyme supplementation did not influence the net energy (NE) value in the diet. The basal diet of the cattle contains by fiber. The fiber diet can be change into simple sugar as energy source. Indirectly, final weight increased by enzyme supplementation.
The second trial (Pererial & Zinn, 2001) involved 72 yearling crossbreed steers calves in a 121 day growing. The purpose is compared the effect of 0 vs 15 g/hd/d fibrozyme on growth performance. The basal diet in the first 84 days contained 22 % forage and 65% steam flaked sorghum. Then, from 85 until 121 day the basal diet contained 12% forage and 75% steam flaked sorghum. The result Showed that fibrolytic enzyme supplementation increased ADG (10%, P<0.10) and carcass weight (2.7%, P<0.05). Enzyme supplementation did not influence DM intake, but increasing dietary NE by 15 % and ADG efficiency 6.3 %. Enzyme supplementation may also enhance cattle performance in a manner independent of the effect on fiber digestion. DM intake influenced by corn, characteristic of sorghum is bulky, so did not influence DM intake in the cattle.
The third trial (Ware et al., 2002) involved 184 crossbreed steers calves in a 261 day. The level of enzyme supplementation is (0, 5, 10, 15 g/hd.d fibrozyme in the diet). The basal diet in the first 70 days contained 22% forage (10% alfalfa hay, 12% Sudan grass) and 64% steam flaked. From day 71 until 261 the basal diet contained 12% forage (4% alfalfa hay, 8% Sudan grass hay) and 75% steam flaked corn. Enzyme supple-mentation increasing ADG by (5%, P<0.05) and gain efficiency (3%, P<0,1). Improvements in ADG were due to treatment effect on feed intake. The effect of enzyme supplementation on dietary NE was small (1%, P=0.13). Optimum growth performance response was obtained with 10 g/hd/d fibrozyme.
In other result, had been reported Pinos-Rodri’guez et all (2002), Lamb fed diet based on all forage showed that the fibrozyme added into hay grasses increased apparent digestibility of CP, hemicellulose (P < 0.05) and NDF (P <0.10) and also improved N balance because lambs retained more N (P< 0.05). The enzyme increased (P<0.05) total VFA concentration for both hays. Results from this trial indicate that directly fed exogenous fibrolytic enzymes may change ruminal fermentation, intake, and digestibility of forages. Increasing of VFA and N retained were indicate fiber or nutrient could utilized more effective.
From these trial Showed different result, the effect of enzyme supplementation influence not only the treatment and variable but also, the age, growing phase, kind of dietary, climate, environment condition and genetic. Genetic factor influence of digestibility fiber. The local species have different genetic with cross breeding. ADG from local genetic maximal 0.8 kg/d in other hand, cross breed have ADG more than 1 kg/d. In this experiment just for cross breed, so the effect enzyme supplementation in local species unknown. Enzyme supplementation influenced of types diets. The diets that high fiber needs supplementation more to degradation the fiber. Ratio concentrate and forage influence enzyme supplementation. Diets that contain high concentrate do not supplementation. Fibrozym supplementation is important thing for diet with high fiber
Fibrozyme supplementation could improve fiber utilization in digestive tract of ruminant. This effect is due to primarily to increase energy intake by enhance ruminal fibrolytic capacity and its increase animal growth. It is suggested that fibrozyme more effectively influenced on ruminant performance if diet based fiber contents.
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