Effects of Different Protein Levels on the Growth Performance and Metabolic Rate of Nutrition in Broilers

The objective of this study is to determine the effect of different protein levels on the growth performance and metabolic rate of nutrition in broilers. Total 360 healthy and weight closed local broilers of 3 weeks were chosen and then divided into three groups randomly by one factor. Each group contains three handlings, each handling consists of 40 broilers. The period of experiment was 7 weeks. The metabolic experiment was performed at the 7th week. Three different protein levels were used in broilers＇ diet. The levels of protein were 19%, 17.5% and 16%. The results showed that the different levels of protein in crude dietary had significant difference between 19% group and the other two groups. The average daily weight gain and daily efficiency were significantly higher than that of the other two groups （P〈0.05）. Compared to protein levels of 19% and 16%, there was no significant difference in the metabolism of calcium （P〉0.05）, and the metabolic rate of the impact of phosphorus was significantly different （P〈0.05）. The result showed that when protein level was 19%, the growth of the local broiler was the best.     

Effects of selenium source and level on growth performance,antioxidative ability and meat quality of broilers

This experiment was conducted to investigate the effects of selenium(Se) source and level on growth performance, carcass traits, antioxidative ability and meat quality of broilers. A total of 320 one-d-old Arbor Acres commercial broilers were randomly assigned to 1 of 5 treatments with 8 replicates in a completely randomized design involving a 2×2 factorial arrangement of treatments plus one Se-unsupplemented basal diet control for 42 d. The two Se sources were sodium selenite and Se yeast, and the two supplemental Se levels were 0.20 and 0.40 mg Se kg–1. The results showed that broilers fed the Se-supplemented diets had higher(P0.05) average daily gain and average daily feed intake from 22 to 42 d of age, eviscerated yield and abdominal fat percentages, Se concentrations and glutathione peroxidase(GSH-Px) activities in breast and thigh muscles on d 42, and lower(P0.05) feed/gain from 1 to 21 and 22 to 42 d of age, mortality from 22 to 42 d of age and malondialdehyde(MDA) concentration in thigh muscle on d 42 than those fed the control diet. Broilers fed the diets supplemented with Se yeast had higher(P0.05) p H value and lower(P0.05) shear force in thigh muscle than those fed the diets supplemented with sodium selenite. Additionally, broilers fed the diets supplemented with 0.40 mg Se kg–1 had lower(P0.05) shear force in thigh muscle and higher(P0.05) GSH-Px activities in breast and thigh muscles than those fed the diets supplemented with 0.20 mg Se kg–1. Furthermore, broilers fed the diet supplemented with Se yeast at 0.40 mg Se kg–1 had higher(P0.05) Se concentrations in breast and thigh muscles than those fed the diet supplemented with Se yeast at 0.20 mg Se kg–1, but no differences(P0.05) were observed in these indices of broilers fed the diets supplemented with sodium selenite between 0.20 and 0.40 mg Se kg–1. The results from the present study indicated that supplemental Se could increase the growth performance, muscle Se concentration and antioxidative ability of broilers; and the Se from Se yeast was more effective than the Se from sodium selenite in improving meat quality of broilers.     

Growth and Haematological Responses of Growing Broiler Chickens （3-6 weeks） to Phosphorus and Phytase Supplementation in Low Nutrient Diet

The experiment was conducted to evaluate the low phosphorus diets supplemented with different sources of phytase in low metabolizable energy （ME） and crude protein （CP） diets in broilers. Four levels of non-phytate phosphorus （NPP） （0.33%, 0.36%, 0.39% and 0.42% of the diet） were employed in six dietary treatments in such a way that the least level of NPP （0.33%） was supplemented with two phytase enzymes namely 6-phytase （Natuphos-5,000） and 3-phytase （Sunphase） along with low nutrient composition viz. 2750 kcal ME/kg and CP 18% in growing phase （21 d-42 d）. A total of 1,400 birds were exposed to six treatments in three replicates except for the phytase supplemented diets which were replicated four times each. Non-significant results are obtained from all performance parameters （body weight gain, feed intake and feed gain） and serum minerals （calcium and phosphorus） between 21 days to 42 days. Non-significant results are seen among all treatments; even supplementation of both types of enzymes did not affect the overall results. The results of the present study demonstrate 0.33% P level without phytase are sufficient in low ME and CP diets.     

Effects of Dietary Fiber and Grit on Performance,Gastrointestinal Tract Development,Lipometabolism, and Grit Retention of Goslings

This study investigated effects of dietary ifbre and grit on growth performance, gastrointestinal tract （GIT） development, serum indexes and grit retention of Sichuan white goslings in China. The experiment was a 3×2 factorial design consisting of dietary crude ifbre （CF） at 2.0, 4.0 and 6.0%levels by adding grass meal and with or without grit supplementation. A total of 720 1-d-old male goslings were randomly allocated into 36 pens of 20 goslings/pen （n=6 pens/treatment）. At 21 d of age, GIT, blood samples and grit in gizzards were collected. Body weight （BW）, empty BW （without GIT）, average daily gain （ADG） and average daily feed intake （ADFI） were affected by CF levels and the medium （4.0%） had the highest value. Adding grit improved BW, empty BW, ADG and ADFI. CF affected relative weight or length of proventriculus, gizzard and duodenum. Increasing CF levels decreased jejunum villus height and affected caecal crypt depth and villus height to crypt depth ratio. Higher CF levels decreased serum triglyceride. Adding grit increased relative weight of abdominal fat. Grit addition increased grit weight in gizzard and the ratio of grit in 0.45-1 and 1-2 mm while decreasing the ratio of grit〈0.45 and 2-3 mm. In conclusion, moderate CF level and grit addition increased performance of goslings without interaction. Dietary CF levels affected the development of upper GIT and serum triglyceride. Grit needed by goslings should be less than 2 mm. Goslings’ gizzard would accumulate grit from feed when other grit could not be acquired.     

Growth Performance,Carcass Yield and Meat Quality of Korean Native Duck

This study was carried out to investigate the growth performance, carcass yield and meat quality of large-type Korean native ducks （KND）. A total of 420 day-old ducklings were divided into four treatments （seven replicates/treatment, 15 birds/replicate） by strains （A and B） and gender （male and female） in a 2 × 2 factorial arrangement under complete randomized design. The body weight （BW） of female KND was higher at week 2 and for male it was higher in week 8 （P 〈 0.05）. BW gain, feed intake and feed conversion ratio of male KND were higher than those of female KND （P 〈 0.05） during week 0 to week 8. The carcass yield of both strains increased from 6 weeks to 8 weeks （P 〈 0.05）. The breast meat ratio was the highest at week 8 whereas the leg meat ratio was the highest at 6 weeks of age in both strains （P 〈 0.01）. Lightness （L＊）, yellowness （b＊） and juiciness of meat were the highest at 6 weeks （P 〈 0.05）. Moisture, ash and fat contents of meat were the highest at 7 weeks （P 〈 0.05） and protein content was the highest at 8 weeks （P 〈 0.01）. These results may provide the basic data on growth performance and meat quality of large-type KND, which can be used for genetic improvements and rearing at commercial scale.     

Effects of dietary yeast β-glucan on nutrient digestibility and serum profiles in pre-ruminant Holstein calves

This study aimed to investigate the effects of dietary supplementation of yeast β-glucan on the nutrient digestibility and serum profiles in pre-ruminant Holstein calves. Forty-two neonatal Holstein calves((39.6±4.2) kg) were randomly allotted to six groups, and each was offered one of the following diets: a basal diet(control) or the basal diet supplemented with 25, 50, 75, 100 or 200 mg of yeast β-glucan kg–1 feed(dry matter basis). The basal diet consisted of a milk replacer and a starter feed. The trial lasted for 56 d. Two digestibility trials were conducted from d 14 to 20 and from d 42 to 48. Blood samples were collected on d 0, 14, 28 and 42 for serum profile analyses. On d 56, three calves from each group were slaughtered, and intestinal samples were collected to assess the villous height, crypt depth and mucosal thickness. Although feed intake was not affected by dietary treatment(P>0.05), the average daily gain(ADG) and gain-to-feed ratios were higher(P<0.05) for the calves fed 75 mg of yeast β-glucan kg–1 feed than those in the other groups. The supplementation of yeast β-glucan at 75 mg kg–1 feed increased the apparent digestibility of dry matter(DM), crude protein(CP), ether extract(EE), and phosphorus(P)(P<0.05) and the ratio of intestinal villous height to crypt depth(V/C)(P<0.05) when compared with the control group. No effects of yeast β-glucan on the serum concentrations of total protein(TP), albumin(ALB), serum urea nitrogen(SUN) and glucose(GLU) were observed(P>0.05). Compared with the control group, supplementation of yeast β-glucan decreased(P<0.05) the serum concentrations of triglycerides(TG) and total cholesterol(TC). The serum concentration of immunoglobulin G(Ig G) and immunoglobulin M(Ig M) increased quadratically(P<0.05), whereas the serum concentration of immunoglobulin A(Ig A) was unaffected by dietary treatments(P>0.05). The supplementation of yeast β-glucan stimulated the enzymatic activity of alkaline phosphatase(ALP)(P<0.05) compared with the control group. The lysozyme(LYZ) concentration increased quadratically(P<0.05) with increasing yeast β-glucan levels. The results suggested that dietary supplementation of yeast β-glucan at 75 mg kg–1 feed improved nutrient digestibility, enhanced immunity by increasing the immunoglobulin concentration and stimulating ALP, and exerted no adverse effects on metabolism in pre-ruminant calves.     

Effects of Multi-enzyme Preparations on Growth Performance,Apparent Total Tract Digestibility and In Vitro Digestibility for Growing Pigs

The aim of this study was to investigate the effects of enzyme supplementations on performance of growing pigs, apparent total tract digestibility （ATTD） and in vitro digestibility （IVD） of nutrients. 224 growing pigs weighing 30-4-1.2 kg were allocated to fed basal diets supplemented with 0, 0.1, 0.15 or 0.2 g/kg enzyme preparations in growth trail. Those four diets were used for in vio＇o digestibility study. Pigs fed enzyme-supplemented diets improved average daily gain and decreased ratio of feed/gain （P〈0.05）. Enzyme supplementations increased ATTD of dry matter, energy, crude protein, neutral detergent fiber, acid detergent fibre and hemicellulose （P〈0.05）. Supplementation with enzymes improved reducing sugar production and the IVD of dry matter, crude protein, neutral detergent fiber, acid detergent fibre, total arabinoxylans, galacturonic acid, hemicellulose and cellulose. 0.015% enzyme supplementation in diets seemed to be sufficient to achieve maximum growth performance, nutrients digestibilities and reducing sugar production. Collectively, these results suggested that the supplementation of enzymes in diet increased the digestibilities of nutrients through the promotion of NSP degradation, thereby enhancing growth performance of growing pigs.     

黄芪·蒲公英等中草药配伍对肉仔鸡生长保健性能的影响(英文)

[Objective] The aim of this study is to investigate the effects of Chinese medical herbs including astragali and taraxacum on health and growth performance of broilers.[Method] The tested Chinese medical herbs were added into the basal diet of avian broilers for measuring the variation of their health and growth performance.[Result]Compared to the control group(fed by basal diet and with antibiotics as additive),the body weight of broilers fed by compatibility A(0.8% astragali;0.4% haw;0.4% dried citrus peel;0.4% rhizoma atractylodis)and by compatibility B(1.2% taraxacum;0.8% smoked plums;0.8% amur cork-tree bark;0.4% astragali)increased by 6.12%(P<0.01)and 0.64%(P>0.05),respectively;feed intakes changed by-7.95% and 9.99%,respectively;feed conversion rates changed by-14.04% and 9.35%,respectively.The survival rate of compatibility B was similar to that of control group.[Conclusion]Compatibility of Chinese medical herbs containing astragali can improve the growth performance of avian broilers,and that containing taraxacum may to some extent result in the decrease of growth performance,but it can play the role instead of antibiotic additives.     

Effects of Maternal Dietary Energy Restriction on Fat Deposition of Offspring

The study was carried out to investigate the effects of maternal dietary energy restriction on growth performance, serum indices and fat deposition of offspring. A total of 400 female Arbor Acres （AA） broiler breeders were studied. These female birds involved three experimental treatments and a control group with normal dietary energy diets （ND, 11.7 MJ of ME. kgt during the laying）. In treatments 2, 3 and 4, the energies of diets were 20%, 30% and 50% （LD20, LD30 and LD50） lower than those of the control, respectively. The study commenced at the beginning of the laying period when the total egg production reached 5% of the flock. All the broiler offspring were fed the same diets. The results showed that in low energy diets, offspring showed decreased 1-day-old weight, but 49-day-old weight was higher in LD20 diet （P〈0.05）. For offspring during days 1-49, the average daily gain （ADG） in LD20 group and the feed conversion ratio in LD50 group were improved as compared with those of the control （P〈0.05）. Compared with the control, abdominal fat percentage increased in 49-day-old offspring from LD30 diet （P〈0.05）; the fat content of breast muscle in offspring increased in broilers fed low energy diets （P〈0.05）. In 28-day-old offspring from breeders given LD20 and LD50 diets, liver fat percentages were higher compared with ND （P〈0.05）. The subcutaneous fat thickness in 28-day-old offspring from LD50 group and 49-day-old offspring from LD30 group was higher （P〈0.05）. On day 49, the serum cholesterol （CHO） of offspring from breeders fed LD20 diet and serum high-density lipoprotein （HDL） of offspring from breeders fed LD50 diet reduced compared with those of the control （P〈0.05）. In addition, a higher triiodothyronine （T3） content in serum was found in offspring from broiler breeders given LD20 and LD30 diets （P〈0.05）. Serum thyroxine （T4） in offspring significantly decreased with the decrease of diet energy （P〈0.05）. In conclusion, to a certain extent, dietary energy restriction in breeders could improve growth performance and promote lipid metabolism of offspring.     

3种吸附剂对黄曲霉毒素B1吸附能力的研究

 【目的】体外试验评价3种吸附剂（吸附剂A：主成分为酵母细胞壁提取物;吸附剂B：主成分为水合铝硅酸盐;吸附剂C为复合物,主成分是酵母细胞壁及水合铝硅酸盐）对黄曲霉毒素B1（AFB1）的吸附效果,并通过吸附剂对摄入AFB1肉仔鸡生长性能及血清蛋白水平的影响验证体外试验结果。【方法】（1）pH为2.0、6.0、8.0的磷酸盐缓冲溶液（PBS溶液）、人工胃液和人工肠液环境下吸附剂对AFB1的吸附能力;（2）吸附剂对AFB1的结合速率;（3）吸附剂结合AFB1形成的复合体的稳定性;（4）240只1日龄雄性AA肉仔鸡,随机分为8个处理,比较吸附剂对摄入AFB1肉仔鸡生长性能及血清蛋白水平的影响。【结果】（1）5种酸碱条件下吸附剂结合AFB1的能力大小顺序为B＞C＞A;（2）吸附剂B在10 min内对AFB1吸附率达到97.69 %,且60 min内一直处在96.03 %以上,而吸附剂A、C在60 min内对AFB1的吸附能力不稳定;（3）与吸附剂A、C相比较,体外条件下吸附剂B与AFB1形成的复合体解吸附率最低;（4）与基础组比较,AFB1组肉仔鸡采食量、体重增加显著下降,料重比显著增加（P＜0.05）,血清总蛋白（TP）、白蛋白（ALB）、球蛋白（GLOB）水平均显著下降（P＜0.05）。3种吸附剂均能提高肉仔鸡生长性能,吸附剂B能显著改善摄入AFB1污染日粮（98.98 μg?kg-1）的肉仔鸡血清蛋白水平的降低,添加吸附剂A或C效果不显著。【结论】3种吸附剂对AFB1均有一定的吸附作用,吸附剂B的作用效果优于吸附剂A和吸附剂C。结果提示,将吸附剂B应用于被AFB1污染的家禽饲料中,与其它霉菌毒素管理措施相结合,能降低AFB1对肉仔鸡的危害。     

转基因稻谷对肉仔鸡生产性能、免疫器官和生化指标的影响

试验研究了用高赖氨酸转基因水稻分别替代40%,100%玉米配制日粮对肉仔鸡生产性能、免疫器官和部分血液生化指标的影响。150只1日龄AA鸡随机分成3组,对照组饲喂玉米-豆粕型日粮,试验Ⅰ组、试验Ⅱ组日粮用转基因水稻分别替代40%,100%的玉米。结果表明:21日龄肉仔鸡体重和体增重,3组之间均未见显著差异(P>0.05),但单位增重耗料,两试验组显著低于对照组(P<0.05);前期,两试验组胸腺指数、脾脏指数、法氏囊指数与对照组相比差异显著(P<0.05),试验Ⅱ组除碱性磷酸酶(ALP)、总胆固醇(CHO)与其他两组存在显著差异(P<0.05)外,其他生化指标均无显著差异;后期,两试验组之间除葡萄糖(GLU)差异显著(P<0.05)外,其他各项生化指标均差异不显著(P>0.05)。说明高赖氨酸转基因水稻分别替代40%,100%玉米能提高肉仔鸡早期生长,且对肉仔鸡各阶段生产性能及血液指标基本无显著影响,从而确保了肉鸡生产性能的正常发挥。     

AFB1与吸附剂对牦牛瘤胃发酵性能的影响

探讨黄曲霉毒素B1(AFB1)和吸附剂对牦牛瘤胃发酵性能影响。采用2因素4水平完全正交试验,饲料中添加4个水平AFB1为20、40、60μg·kg-1、对照组,不同吸附剂处理:蒙脱石(MMT)50 g·头-1·d-1、酵母细胞壁提取物(YCW)50 g·头-1·d-1、MMT 25 g·头-1·d-1+YCW 25 g·头-1·d-1、对照组,测定瘤胃液p H、氨氮(NH3-H)、挥发性脂肪酸(VFA)等14个发酵指标及Fe、Cu、Mn等5种微量元素含量。结果表明,AFB1可降低牦牛瘤胃液p H、NH3-H、总VFA、乙酸、丙酸、戊酸浓度、微晶纤维素酶、纤维二糖酶、木聚糖酶活性、Fe、Cu、Mn、Zn、Se含量(P0.01或P0.05),乙丙比升高(P0.01或P0.05)。3种吸附剂处理均不同程度降低乙丙比,提高总VFA、乙酸、丙酸、丁酸及微生物蛋白(MCP)浓度、羧甲基纤维素酶活性,效应顺序为ⅡⅢⅠ,但仅YCW作用具有统计学意义(P0.01或P0.05)。AFB1对牦牛瘤胃发酵具有抑制作用,浓度越高作用越大;随AFB1浓度增高,瘤胃液微量元素含量降低(P0.01或P0.05),可能存在吸附作用;3种吸附剂处理均可抑制AFB1对牦牛瘤胃微生物毒性,其中YCW效果较优。研究结果将为进一步探讨AFB1影响瘤胃发酵性能相关研究提供参考,为反刍动物饲料安全和吸附剂应用奠定基础。     

7～12周龄古典型岑溪三黄鸡营养需要量研究

选用7周龄的雌性古典型岑溪三黄鸡540只,平均分成9组,通过饲养试验和代谢试验,研究不同的能量、蛋白质和含硫氨基酸水平对古典型岑溪三黄鸡生长性能的影响。结果表明:蛋白质水平对古典型三黄鸡的增重差异显著(P<0.05),能量水平对古典型三黄鸡的采食量和耗料增重比差异显著(P<0.05)。以增重为衡量指标,能量、蛋白质和含硫氨基酸分别以12.13M J/kg、18%和0.55%对古典型三黄鸡的增重效果最好,以耗料增重比为衡量指标,则分别以12.74 M J/kg、18%、0.65%为最佳。     

三种饲料添加剂对霉变饲料饲喂肉鸡的脱毒效果

选用180只8日龄艾维茵肉仔鸡,研究3种饲料添加剂(大豆异黄酮、葡甘露聚糖和膨润土)对饲喂霉变饲料的肉鸡生长性能、免疫功能和骨骼的影响。结果表明,与正常饲料组相比,霉变饲料组显著地降低了肉鸡的采食量、日增重,增加了料肉比(P<0.05);但霉变饲料中添加大豆异黄酮,显著地提高了肉鸡采食量、日增重(P<0.05),降低了料肉比(P<0.05),提高了7周末血清中免疫球蛋白IgA和IgG的浓度。霉变饲料中添加葡甘露聚糖和膨润土显著提高肉鸡日增重(P<0.05),对日采食量有提高的趋势(P>0.05)。但膨润土显著降低了胫骨中钙、磷的含量(P<0.05)。由此可见,3种添加剂对霉变饲料均有一定的脱毒作用,大豆异黄酮对霉变饲料的脱毒效果显著优于葡甘露聚糖和膨润土。     

限饲对肉仔鸡生产性能及部分血清生化指标的影响

随机选取4～8周龄期间经30%能量限制的健康哈博德父母代母雏,研究能量限制对其生产性能及血清生化指标的影响.结果表明:30%能量限制后,肉鸡的体重、平均日增重和腹脂率显著降低;血清超氧化物歧化酶活性显著升高,丙二醛含量极显著降低,尿酸水平极显著升高;血清甘油三酯和总胆固醇水平极显著降低,较对照分别下降32.2%和13.7%;血清尿素氮水平显著升高;血清碱性磷酸酶水平极显著降低.可见30%能量限制可提高肉鸡的抗氧化水平和降低血脂.     

复合植物提取物对肉仔鸡生长性能、血清生化指标的影响

试验选用1日龄320只健康肉仔鸡，随机分成4个处理组，每个处理组设8个重复，每个重复10只鸡。进行了21d的饲养试验，测定了1和32日龄肉鸡血清中谷丙转氨酶、谷草转氨酶和碱性磷酸酶的活性及白蛋白含量。结果表明，复方1植物提取物显著改善了肉仔鸡第1～7天的平均日增重和平均日采食量（P〈0．05），提高了第8～21天的饲料转化效率（P〈0．05），并显著影响32天肉鸡血清谷丙转氨酶和碱性磷酸酶的活性（P〈0．05）。两种复方植物提取物之间对肉仔鸡血清生化指标的影响不显著（P〉0．05）。     

鸡源复合益生菌对青年白羽肉杂鸡免疫球蛋白和Toll样受体通路的影响

为研究鸡源复合益生菌对青年白羽肉杂鸡血清免疫球蛋白和肠道Toll样受体通路的影响,将180只健康的28日龄白羽肉杂鸡随机分为A(基础饲粮)、B(基础饲粮中添加10¹¹ CFU·kg^-1益生菌)、C(基础饲粮中添加2×10¹¹ CFU·kg^-1益生菌)3个处理,每个处理3个重复,每个重复20只鸡。试验期21 d。结果表明:与A组相比,B组和C组鸡血清中IgG、IgM水平显著(P<0.05)升高,B组和C组鸡肠道TLR2、TLR4、Myd88、TRAF-6、AP-1蛋白表达及mRNA相对表达量显著(P<0.05)升高。与B组相比,C组鸡血清IgG、IgM、IgA水平均无明显差异(P>0.05),鸡肠道TLR4、Myd88蛋白表达显著(P<0.05)升高,Myd88基因mRNA相对表达量显著(P<0.05)升高。综上,添加不同浓度的鸡源复合益生菌能够提高白羽肉杂鸡血清中IgG、IgM水平,通过Toll样受体通路增强肉鸡的免疫功能。     

那西肽调控肉鸡非特异性免疫功能的研究

以那西肽作为饲料添加剂按一定比例添加到AA肉鸡日粮中,通过检测血清中溶菌酶、总蛋白和白蛋白等免疫学指标,研究其对AA肉鸡非特异性免疫功能的影响。结果表明:在肉鸡日粮中添加不同比例的那西肽可以显著提高AA肉鸡血清的溶菌酶水平、总蛋白和白蛋白的含量,其中试验2组、3组,即在日粮中添加1.0%,2.0%的那西肽,溶菌酶的含量比对照组提高了102.5%(P<0.05),73.4%(P<0.05);试验1组即在日粮中添加0.5%的那西肽,总蛋白含量比对照组提高了2.06%(P<0.05);日粮中添加2.0%的那西肽组血清白蛋白含量比对照组提高了12.7%,差异显著(P<0.05)。因此,那西肽可调控肉仔鸡的非特异性免疫功能。     

Nonphytate Phosphorus Requirement and Efficacy of a Genetically Engineered Yeast Phytase for Yellow Broilers at 22- to 42-d-Old Age

An experiment was conducted to investigate the requirement of nonphytate phosphorus (OP) and efficacy of a genetically engineered yeast phytase (PHY A) for Lingnan yellow broilers from 22- to 42-d-old age. A total of 1320 1 -d-old male chicks were randomly divided into 11 dietary treatment groups, which consisted of 4 replicate floor pens with 30 birds per pen.The control group (treatment 1) was fed with basal diet of nPP 0.08% without dicalcium phosphate or phytase supplementation. Dietary levels of nPP were 0.16, 0.24, 0.32, 0.40, 0.48, and 0.56%, respectively, for treatments 2 to 7,through addition of dicalcium phosphate (chemistry grade) to the basal diet. Diets of treatments 8 to 11 were supplemented with PHY A at 200, 400 and 600 U kg-t, a commercial phytase product (PHY B) at 400 U kg-1 level, respectively. The birds in 0.32-0.56% nPP groups gained more than those of the other groups (P<0.05). The nPP supplementation significantly improved feed intake (P<0.05). The feed gain ratio was significantly decreased by 0.40% nPP diet compared to the control birds (P<0.05). The level of 0.48% nPP was required for optimum tibia development. The additions of PHY A at 400 and 600 U kg-1 level and PHY B all significantly improved ADG (P<0.05), ADFI (P<0.05), and dry defatted tibia weight (P<0.05).Similarly, the percentage of tibia ash was increased by 600 U kg-1 PHY A supplementation (P<0.05). The requirement of nPP for maximal ADG and highest percentage tibia ash both was 0.40%. The phosphorus equivalency value of PHY A was estimated as 685 U kg-1 for male yellow broilers of 22- to 42-d-old age.