Effect of Different Level of Energy and Crude Fiber From Sawdust in Diets on Carcass Quality of Broiler

This study was conducted to investigate the effect of different level of energy and crude fiber in diets containing sawdust on carcass quality of broilers. A total of 120 broilers were used for the research. The experiment utilized a completely randomized design in 2 x 3 factorial arrangement of treatments consisting of two dietary concentrations of energy and three dietary concentrations of crude fiber. Each treatment consisted of 4 replications (5 birds each) was reared during 35 days. The birds were housed in battery cages with ad libitum access to feed and water. During the experiment, feed intake, carcass yield, abdominal fat, blood LDL-cholesterol and HDL-cholesterol were measured. Data were subjected to the analysis of variance test followed by least significant difference test (LSD). Results showed that the diet with 3,100 Kcal/kg ME and 11% crude fiber significantly decreased feed intake, abdominal fat percentage, and blood LDL-cholesterol, but did not affect final body weight and the value of blood HDL-cholesterol and had the good value of carcass percentage. The diets containing sawdust with higher level of energy content decreased feed intake and the higher level of crude fiber decreased final body weight, carcass percentage and abdominal fat. Optimum broiler performance and carcass quality was obtained by diet formulated to contain 3100 Kcal/kg ME and 11% crude fiber.


INTRODUCTION
Poultry feeding is an important factor in poultry production. The improvement of poultry production is highly depended on synergy between science and practice. By use of modern technology and nutrition knowledge, production of fattening chicken highly increased in the whole world in last 30 years (Steiner et al., 2008).
Dietary fiber is traditionally considered as an anti-nutritional factor (Rougiere et al., 2010). However, moderate amounts of fiber may promote organ development, enzyme production, and nutrient digestibility in poultry. Fibrous feed ingredients have been used in diets of ruminant animals; however, has encouraged researchers to seek a greater understanding of the role of fibrous feedstuffs in diets for non ruminant livestock (Abo Omar, 2005). Use of high dietary fiber feed ingredients in poultry diet has generally been discouraged due to the negative effects exerted on nutrient utilization and performance such as their depression of diet digestibility, and decrease in body weight gain and worsen feed conversion (Kras et al., 2013). However, some types of fiber and fiber sources do not exert such negative effects on nutrient digestibility. Some of these effects result from better gizzard function, with an increase in the gastro duodenal reflux that promotes the contact between nutrients and digestive enzymes (Mateos et al., 2012).
Fiber is a nutritionally, chemically and physically heterogeneous material. It may be divided into soluble fibers which are viscous and fermentable, and insoluble fibers, which are less viscous and fermentable. Both soluble and insoluble fibers have various roles in the digestion and absorption processes in the gastrointestinal tract. Fiber in feed ingredients may affect cecal microbial population and nutrient digestibility. Interactions of these effects can affect bird performance. Thus, nutritionists are faced with a challenge of formulating diets with the available feed ingredients, but also having to mitigate the resulting diet effects to achieve optimum bird production. Wheat bran and cellulose, which are categorized as insoluble fibers, elevate feces weight and fecal bulk and decrease intestinal transit time in non ruminant (Sharikhan et al., 2009). Low apparent metabolizable energy (AME), impaired nutrient absorption and increased incidence of wet droppings may occur due to increase gut viscosity related to feeding soluble non starch polysaccharides (NSP) (Józefiak et al., 2006). Adding fibrous feedstuffs dilutes the diet and may improve the motility and function of the gastrointestinal tract (GIT). Studies by Shakouri et al. (2006) reported that fiber inclusion diet did not compromise growth in broiler chickens. The beneficial effects of fiber were also shown to be related to decreasing gizzard pH, which was accompanied by enhanced nutrient utilization to support and/or increase growth (González-Alvarado et al., 2007).
Determination of the required amount of energy and protein in feedstuff is also probably the most important decision to be made when it comes to feed formulation for broiler (Steiner, 2008). Hence, formulation of animal feed must take into consideration the nutrient density with energy as the prime factor of the particular feed to facilitate production. The performance of broiler chicks were evaluated by Arabi (2015) that protein level of 20% and energy level of 3200 kcal/kg diet may be recommended for finishing broiler chickens. Increasing dietary energy level will increase weight gain and also improve feed conversion (Araujo et al., 2005;Albuquerque et al., 2003).
The attention now is being focused on cheap but suitable alternative feedstuffs. Utilization of cheaper unconventional or certain locally available feed ingredients in place of conventional one has been widely practiced to mitigate this problem. However, the use of unconventional feedstuff for efficient poultry production is limited due to presence of udigestible components like fiber non starch polysaccharides (Adebiyi et al., 2010). Many forms of residues are produced from wood processing plants. For instance, residues from wood processing plants (the shredded bark, sawdust, and shavings) frequently have no markets, but most untreated woods are quite indigestible. However, Oke and Oke (2007) stated that the sawdust up to 80 g kg -1 level of inclusion in broiler diets did not have any detrimental effect on weight gain. Since sawdust is abundant and available throughout the year in many developing countries, the utilization of sawdust will reduce the cost of production. National data of Indonesia according to BPS 2006, production of sawdust from furniture industry were 679.247 m3 in 600 kg/m3 density, equal to 407,508.2 ton.
Generally, whole-tree or tree residues are not considered dangerous to the health of livestock. It is essential, however, that diets containing wood residues be properly balanced for all of the Energy and Crude Fiber from Sawdust (J. S. Mandey et al.) essential nutrients. Wood residues must be considered primarily as energy sources.
The physiological and practical implications of the link between crude fiber and energy intake under iso-protein must then be considered when the dietary requirements for either nutrient are assessed. Moreover, there is a lack of sufficient information about the effect of dietary energy density and crude fiber level on the performance of broiler chickens. Therefore, the aim of this investigation was to study the effect of feeding high and low dietary energy with high and low crude fiber levels on carcass quality of broiler chickens.

MATERIALS AND METHODS
A total of 120 D.O.C of broilers were used for the research. The experiment utilized a completely randomized design in 2 x 3 factorial arrangement of treatments consisting of two dietary concentrations of energy (low and high) and three dietary concentrations of crude fiber. Each treatment consisted of 4 replications (5 birds each) was reared during 35 days. The birds were housed in battery cages in an environmentally controlled room. Feed and water were given ad libitum. During the experimental period (1 to 35 days) chickens were fed iso-protein mixed rations containing different levels of energy and fiber. The crude fiber source of feedstuffs mostly from sawdust and then were mixed with other crude fiber sources. The chemical compositions (dry matter basis) of sawdust were protein 0.66%, crude fat 0.37%, crude fiber 80.31%, NFE 15.79%, Ca 0.79%, P 0.03%, GE 128.51 Kcal/kg. The values for different levels of crude fiber and energy are presented in Table 1. The value of metabolizable energy was estimated from the gross energy of feed ingredients.
The performance characteristics were feed intake, final body weight, carcass weight, abdominal fat, blood HDL-cholesterol and LDLcholesterol. These parameters were measured  Carcass was weighted after removal of feather, head, lungs, gastrointestinal tracts, liver, kidney, abdominal fat. The eviscerated weight was measured to calculate the dressing percentage as the percent of dressed carcass weight to live weight of the bird. Abdominal fat included fat surrounding gizzard, bursa of fabricius, cloaca and adjacent muscles) was removed and weighed individually for 4 chicks per treatment. Blood samples were collected from the wing vein of 5 chicks, in each group, at the end of the experiment (35 days) to analyze cholesterol content.
Data were analyzed by analysis of variance of completely randomized design in 2 x 3 factorial arrangement. It was continued to least significant difference test (LSD) (Steel and Torrie, 1994) if the treatment indicated significant effect at a probability level of 5%. The IBM SPSS Statistics 22 software was used for the statistical processing of data.

RESULTS AND DISCUSSION
The effects of different energy and fiber levels in diets on carcass quality of broiler chickens is presented in Table 2. Results showed that the daily feed intake was significantly affected by levels of energy and crude fiber, and significantly affected carcass and abdominal fat percentage, and blood LDL-cholesterol. The interaction of energy and crude fiber level final body weight and the value of blood HDLcholesterol. The diet containing 3100 Kcal/kg ME and 11% crude fiber decreased feed intake, abdominal fat percentage, and blood LDLcholesterol, but did not affect final body weight and the value of blood HDL-cholesterol and had good value of carcass percentage.
The result showed that an increase in dietary fiber reduced feed intake in poultry as reported by Energy and Crude Fiber from Sawdust (J. S. Mandey et al.) 243  -Moreno et al., 2011;Mateos et al., 2012). However, different authors have demonstrated that the inclusion of moderate amounts of insoluble dietary fiber did not affect voluntary feed intake in broilers (Gonzalez-Alvarado et al., 2007;Jimenez-Moreno et al., 2007;Jimenez-Moreno et al., 2009). Moreover, Tooci et al. (2009) reported that dietary dilution of energy treatments did not show significantly difference on feed intake. Tabook et al. (2006) observed high feed intake and no effects on performances when insoluble fiber was included at moderate levels in broiler diets. The result showed that percentage of abdominal fat significantly decreased although dietary energy level increased, and that was due to high crude fiber level. This result was similar to Shahin and Abdelazim (2006), who reported that abdominal fat, carcass fat and total body fat yields greatly decreased by feeding birds with high fiber diets and produces less abdominal fat depots. At the other side, Mourao et al. (2008) reported that birds fed diets containing insoluble fiber produced lighter carcasses with lower levels of abdominal fat compared with control. Maiorka et al. (2005) announced that dietary energy level affected abdominal fat weight. The abdominal fat increased in the treatments was due to the increasing of dietary energy level.
Since diets high in insoluble fiber contain low energy, birds tended to increase feed consumption to compensate the reducing nutrient concentration in feed. Feed ingredients containing high of insoluble fiber caused an increase in the bulk of the materials that eventually leads to fast passage through the gastrointestinal tracts, unless the animal has a large digestive system capacity. There are suggestions that fiber decreases nutrient digestion because it encapsulates nutrients into the plant cell causing a reduction in the activity of digestive enzymes. Insoluble fiber has been reported to have some beneficial effects. Some experiments have shown that as long as insoluble fiber is included in poultry diets at moderate concentrations, performance of birds will not be affected despite the fact that the nutrient concentration of the diet reduced (Hetland et al., 2004). However, the mechanism of formulating diets with moderate levels of insoluble fiber is not well known.
In this study, the inclusion of crude fiber up to 11% in diet did not affect final body weight. Oke and Oke (2007) reported that sawdust up to 80g kg -1 level of inclusion in broiler diet did not have any detrimental effect on weight gain. But, Gonzalez-Alvarado et al. (2007) reported that the inclusion of moderate amounts of fiber in low fiber diets might improve chick performance at early ages by reducing gizzard pH and improving the utilization of nutrients. Sarikhan et al. (2010) reported that suplementing broiler diets up to 0.75% insoluble raw fiber concentrate did not affect feed intake, increased weight gain and improved FCR. Shahin and Abdelazim (2005) stated that birds fed a high fiber diets had lower carcass weight than birds fed low fiber diets. This result is in contrast with our results and this differences may be related to fiber source and amounts of fiber in diet. Some of the carcass compositions of the broiler chicken were affected by the different dietary levels of energy and fiber. The significant reduction in carcass in birds fed the diet containing 2800 Kcal/kg ME and 11% crude fiber may be attributed to low dietary calorie.
The body fat deposition significantly increased in birds fed high and normal energy content in the diets resulting into a high calorie: protein ratio which agrees with the report of Swenen et al. (2006). According to Deaton et al. (1983), the highest abdominal fat (2.29% of live weight) was produced by broilers offered diet containing 3325 ME Kcal/kg. The least amount of abdominal fat (1.92% of live weight) was produced by broilers offered diets containing 3100 and 3175 Kcal/kg ME.
The energy content of diet is a key factor to control feed intake in poultry, as broiler chickens eat as much as their energy requirement (Leeson and Summer, 2005). Thus, lower feed intake in this group could be described by higher energy content in the diet.

CONCLUSION
The diets containing sawdust with higher level of energy content decreased feed intake and the higher level of crude fiber decreased final body weight, carcass percentage and abdominal fat. Optimum broiler performance and carcass quality was obtained by diet formulated to contain 3100 Kcal/kg ME and 11% crude fiber.