JJ Wang,*1 JD Garlich,? and JCH Shih?
(*BioResource International, Morrisville, NC 27560; Department of Poultry Science, North Carolina State University, Raleigh, 27695)
Main audience : feed producers, livestock and poultry managers, animal nutritionists, researchers
Abstract: Versazyme (VZ) is a protease additive. Three different protein and amino acid broiler diets were prepared based on the average provided by the US Poultry Industry Analysis Department, with low protein levels (95%), medium protein levels (100%), and high protein levels (105%), respectively. The lowest value of amino acids in each diet ensures the need for a corresponding protein level. The protein levels of broilers at different growth stages were designed as follows: brooding period 21%, 22%, 23%; growth period 19%, 20%, 21%; fattening period 17%, 18%, 19%; withdrawal period 16 %, 17%, 18%. A 3×2 factorial design method was used to feed three protein levels and diets with or without VZ, and the male and female chicks were mixed for a test period of 48 days. The results showed that the 48 d high-protein diet treatment group had the highest score of 2.42 kg; the low-protein diet treatment group had the lowest, 2.36 kg; and the medium-protein diet treatment group was centered at 2.40 kg. VZ significantly increased body weight for 48 days (2.54%, from 2.36 kg to 2.42 kg, P < 0.01), feed conversion efficiency (1.62%, from 1.912 to 1.881, P < 0.01), and breast meat yield (1.68%, From 31.57% to 32.10%, P < 0.01). The effect of VZ on body weight and feed conversion efficiency was best in the low protein diet treatment group. However, the improvement effect of VZ on breast meat yield was best in the medium protein level and high protein level diet group. VZ additives significantly increase the amino acid utilization efficiency of broilers fed commercial feed.
Key words : broiler, breast meat yield, dietary protein level, protease
2006 J. Appl. Poult. Res. 15:544-550
1. Foreword
Poultry commercial feeds are generally formulated according to the principle of minimum cost, in which the protein is derived from different components of the formulation, resulting in a very large variation in the biological effectiveness of the amino acid. For example, for the average true digestibility of cysteine, lysine, and threonine, soybean meal is 82%, 91%, and 88%, respectively, and corn is 85%, 81%, and 84%, respectively. 58%, 79%, and 79%, while feather meal was 59%, 66%, and 73%, respectively [1]. The true digestibility of amino acids in each raw material varies widely, especially as animal by-products vary more. It is well known that poultry does not fully utilize the protein in the diet. Therefore, the addition of proteolytic enzymes in poultry diets may increase the efficiency of amino acid utilization, and the proteolytic enzyme needs to have certain characteristics, such as appropriate activity. Stability and low application costs. A large number of studies have been carried out in poultry using a variety of protease preparations, but the results are not consistent [2, 3, 4]. Recent studies have shown that the addition of protease or keratinase to chick diets can significantly improve growth rates [5,6]. VZ is derived from the thermophilic Bacillus licheniformis PWD-1 in the natural environment at a temperature of 50 ° C. It has high protease activity and a wide range of hydrolyzable protein substrates [7, 8, 9]. The addition of VZ to chick low-protein corn-soybean diets can significantly increase the weight of broilers [10]. The addition of VZ to chick diets containing corn, soybean meal and cotton aphid significantly improved body weight, feed conversion efficiency (FCR) and protein digestibility [11]. This study used 0-7 weeks old broiler chickens, using three protein levels (95%, 100%, and 105% of the average commercial feed) diet and two levels (0 and 0.10%) of VZ. The effect of protein level and VZ on broiler performance and carcass quality, and the interaction between the two was evaluated.
2. Materials and methods
2.1 Feeding and Management
The study was conducted on a commercial trial farm, and the management of the test chickens was in accordance with the "Regulations on the Management and Use of Agricultural Research and Teaching Animals" [12]. 5088 One-day-old male and female chicken chicks [13] were housed in a chicken house with fresh litter. The house was equipped with 23L: 1D light control program, side curtain insulation and commercial production mode. There are 48 8 × 10 square feet of ground fences in the house, each offering 0.75 square feet of flat space per bird. A total of 106 chicks (53 females and 53 males) were raised in each column. The chicks were raised from the age of 1 day and the 50-day-old trial ended.
2.2 Test diet
The corn-soybean-type test diet was prepared according to the broiler chickens provided by the American Poultry Industry Analysis Department to 2.00-2.72 kg "average of all production enterprises" (2003) [14], and the nutrient level diet was set to medium protein ( MP) Test diet, MP diet group as a control group, can provide 100% of the nutritional needs of the US poultry industry. The other 2 treatment histones and amino acid levels were lower or higher than 5% in the MP treatment group. Low protein (LP), MP, and high protein (HP) diets were divided into four production stages: 21%, 22%, and 23% during the brooding period; 19%, 20%, and 21% during the growing period; The period was 17%, 18% and 19%; the withdrawal period was 16%, 17% and 18%. The lowest value of amino acids in each diet guarantees the need for the corresponding protein level (Table 1). In addition to protein and amino acid content, each nutrient content meets or exceeds NRC [1] broiler nutritional requirements. In addition, throughout the trial phase, LP, MP, and HP treatments were further divided into test diets with or without VZ. Both the broken material (0 to 18 d) and the pellet (19 to 50 d) were fed ad libitum. Due to its thermal stability, VZ can be added to the feed before granulation and the granulation temperature is controlled at 180 °F. The VZ activity, CP and energy (elastic calorimetry) of the test diet samples were analyzed. The results showed that all test diets met the protein level requirements for the test (Table 2).
Chemical Raw Materials,Potassium Permanganate,Hydrogen Peroxide
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