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1.
Strieker MJ Morris JG Kass PH Rogers QR 《Journal of animal physiology and animal nutrition》2007,91(11-12):465-474
The objective of this study was to determine if the methionine (met) requirement of kittens is correlated with the concentration of dietary crude protein (CP). The study used 48 male kittens in two replications of six 4 x 4 Latin squares, each representing one concentration of met (1.5, 2.5, 3.5, 4.5, 6.0 or 9.0 g/kg diet) with four CP concentrations (150, 200, 300 and 500 g/kg diet) in 2-week periods. Cystine was present in the lowest CP diet at 5.3 g/kg diet and increased as dietary CP increased. Body weight gain, food intake, nitrogen balance and plasma amino acids, glucose, insulin, cortisol, somatomedin C, T(3) and T(4) concentrations on day 12 were measured. From breakpoint analysis of the nitrogen retention curves, the met requirement of kittens was found to be 3.1, 3.8, 3.1 and 2.4 g met/kg for the 150, 200, 300 and 500 g CP/kg diets, respectively. When met was limiting (1.5 or 2.5 g/kg diet), increasing dietary CP did not decrease, but rather increased food intake, body weight gain and nitrogen retention. Plasma met concentrations increased as dietary met increased and at 2.5-3.5 g met/kg diet were not different among kittens fed the various CP diets. Total plasma T(3) and T(4) increased significantly as dietary CP increased in kittens given the 2.5 and 4.5 g met/kg diets. Results indicate that food intake and possibly altered hormonal secretion play a role in this growth response. In conclusion, the met requirement of growing kittens, unlike omnivores and herbivores studied, was not positively correlated with the concentration of dietary CP. 相似文献
2.
Strieker MJ Morris JG Rogers QR 《Journal of animal physiology and animal nutrition》2006,90(7-8):344-353
Essential amino acid (EAA) requirements of omnivores and herbivores (e.g. chicks, lambs, pigs and rats) are directly related to the concentration of dietary crude protein (CP). When an EAA is limiting in the diet, addition of a mixture of EAA lacking the limiting one (which increases dietary CP) results in a decrease in food intake and weight gain. This interaction has been referred to as an AA imbalance and has not been studied in depth in strict carnivores. The objectives of these experiments were to examine the effects on growing kittens (2-week periods) of the addition to diets of a mixture of AA lacking the limiting one. The control diets were at the requirement of the respective limiting EAA (or about 85% of the 1986 National Research Council requirement). In experiment 1, with the dietary EAAs at the minimally determined requirements, the concentration of the essential or dispensable amino acids was increased to determine if CP or an EAA was limiting. Results of growth rates (n = 12) and plasma AA concentrations indicated that tryptophan was limiting, but increased body weight gain also occurred when the concentration of CP was increased as dispensable amino acids without additional tryptophan. Experiment 1 was repeated in experiment 2 using a crossover design. Again, when tryptophan was limiting additional concentrations of dispensable AAs increased body weight gain. This response is the opposite of that in herbivores and omnivores. Experiment 3 consisted of 10 separate crossover trials, one for each of the 10 EAA and examined the effect of two concentrations of dietary CP (200 and 300 g CP/kg diet) on body weight gain of kittens (n = 8) offered diets limiting in each respective EAA. Body weight gain was numerically greater when diets contained 300 g CP/kg than 200 g CP/kg for eight of 10 EAAs (p < 0.05 for only isoleucine and threonine) when each amino acid was limiting. This response is the reverse of that which occurs in chicks, lambs, pigs and rats when an EAA is limiting and dietary CP lacking the limiting EAA is increased. These results indicate that the EAA requirements of kittens are not positively correlated with dietary CP concentrations. 相似文献
3.
Strieker MJ Werner A Morris JG Rogers QR 《Journal of animal physiology and animal nutrition》2006,90(11-12):440-445
Foot pad dermatitis has been observed in turkeys, puppies and kittens fed diets deficient in methionine. Excess cystine aggravated the lesions and decreased body weight gain in puppies and turkeys. The objective of this study was to determine whether methionine deficiency induced perioral and foot pad lesions in kittens and whether excess cystine exacerbated the lesions. Eighteen kittens were divided into three groups and offered one of three diets: diet 1, low-methionine, low-cystine (LMLC; 1.6 g methionine and 1.6 g cystine/kg diet); diet 2, low-methionine, high-cystine (HMHC; 1.6 methionine and 15 g cystine/kg diet); diet 3, high-methionine, high-cystine (HMHC; 15 g methionine and 15 g cystine/kg diet). Kittens in the LMLC group lost body weight, whereas those in the LMHC group maintained their body weight and those in the HMHC group gained weight. Plasma methionine concentrations were significantly higher (p < 0.001) for the HMHC group than for the LMLC and LMHC groups. Plasma cyst(e)ine (sum of cysteine and cystine) concentrations were different (p < 0.001) among all the three groups. Two kittens given the LMLC diet developed mild perioral lesions. All kittens receiving the LMHC diet developed foot pad lesions and severe perioral lesions. Histopathological changes observed in perioral biopsy specimens were similar to those described in protein deficiency. In conclusion, the results showed that a diet severely deficient in methionine causes perioral lesions in kittens, and that addition of excess cystine to the diet aggravates the perioral lesions and also causes foot pad lesions. 相似文献
4.
An experiment was conducted to determine the effects of different amounts of dietary methionine on growth performance, serum protein, growth hormone (GH), insulin‐like growth factor‐I (IGF‐I) concentrations and IGF‐I mRNA expression of growing meat rabbits. One hundred weaned growing meat rabbits were allocated to individual cages and randomly divided into five groups. The methionine addition concentrations of the five groups were 0, 2, 4, 6 and 8 g/kg diet (as‐fed basis) and sulphur amino acids (SAA) concentrations ranging from 3.8 to 11.6 g/kg diet, respectively. The results obtained were as follows: the average daily gain of 2, 4 and 6 g/kg diet groups was higher than that of 0 g/kg diet group (p < 0.01). The feed gain ratio of the 4 g/kg diet group was lower than those of 0 and 8 g/kg diet group (p < 0.01). Methionine concentrations did not affect serum urea nitrogen, total protein, insulin and IGF‐I concentration (p > 0.05). The quadratic effects of methionine on the serum concentration of albumin (Alb) and GH were obtained (p = 0.013, p = 0.018). The quadratic effect of methionine amount on IGF‐I mRNA expression was obtained (p = 0.045). The serum concentration of Alb of the 4 g/kg diet group was higher than those of 0 and 8 g/kg diet group (p < 0.01). The serum concentration of GH of 8 g/kg diet group was higher than that of the 0 g/kg diet group (p < 0.05). The liver IGF‐I mRNA expression of 4 g/kg diet group was higher than those of the 0 and 8 g/kg diet group (p < 0.05). Providing a diet mainly consisted of corn, wheat bran and peanut vine, the optimum dietary methionine addition concentration and SAA concentration for a weaner to 2‐month‐old growing meat rabbits were shown to be 2 and 5.7 g/kg diet respectively. 相似文献
5.
1. Experiments were conducted independently at two stations to measure the requirement for methionine in chick diets with crude protein (CP) varying in 8 steps from 140 to 280 g/kg diet (experiment 1) or from 90 to 300 g/kg (experiment 2). 2. Protein composition was the same at all protein concentrations within a trial. The diet was designed to be first-limiting in methionine and DL-methionine was added to provide 5 ratios of methionine to CP at each protein concentration. 3. Methionine required for maximum growth rate or maximum efficiency of food utilisation was estimated at each protein concentration by fitting a quadratic regression equation to the relevant data. The requirement was also estimated by fitting the Reading model to data for growth rate and methionine intake. 4. In both trials and by all three methods of estimation, the methionine requirement (g/kg diet) for maximum performance increased as a linear function of dietary CP concentration and nearly in direct proportion to CP. 5. It is concluded that diets which contain surplus protein, beyond that needed to maximise growth rate or food efficiency, need supplementation with methionine beyond that required when dietary protein is just adequate. A suitable rule for practical formulation is that methionine concentration in chick diets should be not less than 0.025 times the dietary CP concentration. 相似文献
6.
An experiment was conducted to develop a system useful for measuring methionine requirements of growing steers. Seven ruminally cannulated steers (312 kg, gaining .91 kg/d) were fed a diet based on ammoniated corn cobs, corn starch, molasses and urea. Quantities of N and sulfur-containing amino acids disappearing from the small intestine were 96.0 and 14.8 g/d, respectively. Postruminal infusions of Na-caseinate (CAS) resulted in linear (P less than .01) increases in N retention with values increasing from 30.1 g/d with no postruminal CAS infusion to 39.3, 50.8 and 59.2 g/d (averaged across methionine supplementation) when 100, 200 and 300 g/d CAS were infused. Postruminal infusions of a mixture of crystalline L-amino acids (simulating the nonsulfur-containing essential amino acid pattern of casein; SIM) at levels of 100, 200 and 300 g/d also led to linear increases (P less than .01) in N retention with steers retaining 30.9, 38.9 and 50.5 g N/d (averaged across methionine supplementation), respectively. Postruminal infusion of 12 g/d L-methionine across CAS and SIM infusions improved (P less than .01) N retention by 7.6 g/d but infusion of SIM, which is devoid of sulfur amino acids, also increased N retention. Responses to methionine supplementation was greatest when 200 or 300 g/d SIM were abomasally infused. The data are interpreted to demonstrate that, for steers fed a diet containing little true protein, postruminal supplementation with nonsulfur-containing amino acids tended to increase the ability of growing steers to respond to methionine supplementation. 相似文献
7.
1. The dietary methionine requirement of egg-laying ducks was assessed by feeding diets supplemented with graded levels of DL-methionine (0, 4, 8, 12, 16 g/kg dietary protein) for 8 weeks. The basal diet contained 175 g protein and 2.6 g methionine per kg feed (or 14.9 g/kg protein) and an estimated ME of 11.5 MJ/kg. 2. A total of 800 Shaoxin laying ducks (420 d old) were randomly divided into 5 groups of 160 each and fed in 4 separate pens. 3. Dietary supplementation of methionine significantly increased egg production and feed conversion efficiency. 4. Dietary methionine requirement for optimum egg production was estimated to be 25.7 g/kg of dietary protein or 4.5 g/kg of the diet or 380 mg/bird-d. 5. Methionine supplementation increased the methionine level in plasma, and the free glutamic acid and aspartic acid concentrations in plasma were quadratically related to dietary methionine levels. Increasing dietary methionine had little effect on egg quality characteristics. 相似文献
8.
为研究低蛋白质日粮添加赖氨酸和蛋氨酸对仔鹿氮代谢的影响,采用4×4完全拉丁方试验,选取3月龄、健康、离乳梅花鹿仔鹿4只,体重为(30±0.12)kg(X ?
9.
Two hundred and six female breeder turkeys were fed on maize-soybean diets of equal energy content, containing 100, 120 or 140 g crude protein (CP)/kg to which DL-methionine was added at 0, 1, 2 or 3 g/kg diet in a factorial design. Serum albumin concentrations were found to be more sensitive measures of dietary protein adequacy than were total serum protein concentrations. Albumin concentrations at peak egg production were highest among birds fed on 120 and 140 g CP/kg diets. Four weeks later, they were highest only for those on the 140 g CP/kg diet. The elevated concentrations of blood threonine and lysine and the decreased concentration of glycine with increased dietary protein were in agreement with the data on egg production. These data suggested that a sub-optimal balance of dietary amino acids may have occurred. 相似文献
10.
An experiment was conducted to determine the effects of different dietary neutral detergent fibre (NDF) levels on growth performance, nutrient utilization, caecum development, caecal fermentation, slaughter performance, immune organ and fibrolytic activity in 2- to 3-month-old New Zealand meat rabbits. Eighty 2-month-old rabbits were allocated in individual cages for five treatments in which they were fed each diet with NDF at 240, 270, 300, 330 and 360 g/kg respectively. The results are as follows: the average daily gain of 300 g/kg NDF group was the highest (30.09 g/day) and higher than that of 240 g/kg NDF group (p < 0.05). The feed/gain ratio of 300 g/kg NDF group was the lowest (4.27) and lower than those of 240 and 360 g/kg NDF groups (p < 0.05). The coefficient of total tract apparent digestibility (CTTAD) of energy, crude protein, crude fibre and ether extract decreased when dietary NDF increased (p < 0.05); CTTAD of NDF increased when dietary NDF increased (p < 0.01). Digestible nitrogen and retained nitrogen of 240, 270, 300 and 330 g/kg NDF groups were higher than that of 360 g/kg NDF group (p < 0.05). The caecum weight, the proportion of caecum weight to body weight and the acetic acid ratio of volatile fatty acid rose when dietary NDF concentration increased (p < 0.05). The NH(3)-N concentration of caecum dropped when dietary NDF increased (p < 0.05). The fibrolytic activity increased when the dietary NDF increased (p < 0.01). 相似文献
11.
1. An experiment with separately housed male and female broiler chicks was carried out during the period of 3 to 7 weeks of age to determine the limiting amino acids (AA) in a low protein maize-soyabean meal diet. Chicks were fed on diets containing 170, 180, 190 and 200 g crude protein (CP)/kg with or without combined additions of L-threonine (Thr), L-tryptophan (Trp) and L-arginine (Arg) to those in the 180, 190 or 200 g CP/kg diets and a 170 g CP/kg diet with or without combined additions of Thr, Trp, Arg, L-isoleucine (Ile), L-leucine (Leu) and L-valine (Val) to those in the 190 g CP/kg diet. The diets were iso-energetic and contained the same concentrations of lysine (Lys) and sulphur-containing amino acids. 2. Decreasing the dietary CP had a significantly negative effect on performance. 3. No significant effects on performance were found when diets with 180 and 190 g CP/kg were supplemented with Thr, Trp and Arg to those in the 200 g CP/kg diet. 4. There were no significant differences in performance between the groups fed on the diets with 170, 180 and 190 g CP/kg when the 170 and 180 g CP/kg diets were supplemented with Thr, Trp and Arg to those in the 190 g CP/kg diet.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
12.
1. This study was conducted to determine the effects of starter and grower diets with differing crude protein (CP) and metabolisable energy (ME) concentrations on the body weight (BW), live weight gain (LWG), feed consumption (FC), feed conversion ratio (FCR), and carcase, breast+back, rump, wing, neck and abdominal fat weights of chukar partridge raised in captivity. 2. Chukar partridges were fed on starter diets containing 4 concentrations of CP (160, 200, 240, 280 g/kg) and 4 concentrations of ME (10.9, 11.7, 12.6, 13.4 MJ/kg) from hatch to 8 weeks of age; they were fed on grower diets containing 4 concentrations of CP (150, 175, 200, 225 g/kg) and 4 concentrations of ME (11.9, 12.6, 13.2, 13.8 MJ/kg) from 9 to 16 weeks of age. All diets contained at least 5.5 g/kg methionine, 15 g/kg lysine and 10 g/kg methionine+cystine. Sixteen starter and 16 grower diets were arranged in a 4 x 4 factorial design with 4 levels of CP and 4 levels of ME. Each treatment was replicated three times with each replicate consisting of 5 males and 5 females. 3. Partridges fed on a starter diet containing 160 g CP/kg were significantly lighter at 8 weeks of age than those in groups given diets containing a higher CP. However, at 16 weeks of age, the differences in BW among treatments had disappeared. Throughout, there were no significant effects of ME concentration on BW and LWG. 4. The daily mean FC for the 0 to 8 week and 0 to 16 week periods was not affected by dietary CP concentration. For the 9 to 16 week period, the partridges fed on a grower diet containing 225 g CP/kg consumed more feed than those given a diet containing 175 g CP/kg. 5. The highest FCR for the 0 to 8 week period was in partridges fed on a starter diet containing 160 g CP/kg. For the 9 to 16 week period, the lowest FCR was in partridges fed on a grower diet containing 150 g CP/kg. For the 0 to 16 week period, there was not a significant effect of dietary CP concentration on FCR. The daily mean FC and the FCR for the 0 to 8, 9 to 16 and 0 to 16 week periods decreased when the ME concentration of the starter and grower diets increased. 6. The carcase, rump and breast+back weights of the male partridges increased when the ME content of the diets increased. Weights of all carcase components of the male partridges were significantly greater than those of the carcase components of the females. 7. There were no significant interactions between CP and ME concentrations on BW, LWG, FC, FCR and carcase characteristics. 8. We conclude that the starter diet for chukar partridges raised for meat production should contain at least 200 g CP/kg, 11.7 MJ ME/kg, and the grower diet should contain 150 g CP/kg, 12.6 MJ ME/kg. 相似文献
13.
日粮添加不同水平蛋氨酸硒对肉牛营养物质代谢的影响 总被引：1，自引：0，他引：1
选用4头安装永久瘤胃瘘管的西门塔尔阉牛(体重为420kg、年龄2.5岁),采用4×4拉丁方设计,以混合精料和风干玉米秸秆作为基础日粮,研究1.3倍维持需要水平下,日粮添加不同水平蛋氨酸硒(0、0.3、0.6、0.9mg/kg,以干物质为基础)对营养物质代谢的影响。结果表明:0.3和0.6mg/kg组日粮OM、CP、EE、NFE、NDF、ADF表观消化率显著高于对照组(P<0.05);0.6和0.9mg/kg组DN、RN和RN/DN显著高于对照组(P<0.05);0.6mg/kg组与对照组相比Se、Ca、P、Cu、Fe、Mn的存留率显著提高,Zn、Mo和S的存留率无显著差异;0.6mg/kg组血清TG、GLU、ALB、TP、ALT、AST、SOD、GSH-px、GSH均显著高于对照组(P<0.05);0.6mg/kg组血清Se、Cu含量显著高于对照组(P<0.05)。 相似文献
14.
试验旨在研究日粮中添加蛋氨酸铬对肉鸡生长、脏器指数及血清生化指标的影响,为确定日粮中蛋氨酸铬的适宜添加量提供科学依据。试验选用1日龄AA肉鸡528只,设4个处理,每个处理4个重复,每个重复33只。对照组饲喂玉米-豆粕型基础日粮,其它处理组饲喂分别在基础日粮中添加蛋氨酸铬0.1 mg/kg(Ⅰ组)、0.2 mg/kg(Ⅱ组)、0.6 mg/kg(Ⅲ组)的日粮(以Cr3+计),试验期49 d。结果表明:蛋氨酸铬能显著降低饲料消耗(P<0.05),但对肉鸡各日龄段平均体重、料重比和成活率影响差异均不显著(P>0.05)。除能显著降低心脏相对重量(P<0.05)外,日粮中添加蛋氨酸铬对肉鸡其它脏器相对重量影响差异均不显著(P>0.05)。日粮中添加蛋氨酸铬对血液生化指标影响显著(P<0.05)。因此,日粮中补充蛋氨酸铬对肉鸡生产性能、脏器指数影响不明显;但对血液生化指标影响显著,建议日粮中蛋氨酸铬添加量以0.2 mg/kg为宜。 相似文献
15.
1. Two experiments were conducted to determine the influence of dietary protein and amino acids on urinary excretion of amino acids and nitrogen in colostomised turkey hens.
2. Normal and colostomised turkeys 8 weeks of age were fed on control and high protein diets. Body weight gains of both types of birds were similar. Diet did not affect the amino acids in the urine significantly, but urinary nitrogen was higher with the high protein diet.
3. Normal and colostomised turkeys 10 weeks of age were fed a diet with either supplemental DL‐methionine or L‐lysine hydrochloride (each 20 g/kg diet). DL‐methionine depressed gain and resulted in considerable excretion of methionine in urine. Lysine had little effect on weight gain or urinary lysine. 相似文献
16.
L. C. Nwanna M. Kolahsa R. Eisenreich F. J. Schwarz 《Journal of animal physiology and animal nutrition》2008,92(6):677-682
Effect of phytase pre-treatment of dietary plant feed stuffs (PF) on growth and mineral concentration in common carp (C. carpio L.) was investigated. Diets used were: C0, diet with no supplement; CI, diet with incubated PF; CP0, diet supplemented with 3 g P/kg; CPI, diet with incubated PF supplemented with 3 g P/kg; Phyt0, diet fortified with 4000 U phytase/kg; PhytI, diet with PF incubated with 4000 U phytase/kg. Mean weight gain, SGR and FCR were the same (p < 0.05) in fish fed CP0, CPI or PhytI but less (p < 0.05) in other fish. Bone P was similar in fish fed CP0 (74.9), CPI (75.9) or PhytI (71.5 mg/g DM) but higher (p < 0.05) than in fish fed C0. Bone Ca and Mg were similar in fish fed CP0, CPI or PhytI but less (p < 0.05) in other fish. Bone Zn in fish fed C0, Phyt0 or PhytI was higher (p < 0.05) than that in fish fed CP0 or CPI. In conclusion, CP0, CPI and PhytI had the same effect, suggesting phytase pre-treatment as the most effective method. CPI did not have any advantage over CP0. Phytase increased mineral availability and utilization, which would minimize cost of mineral supplementation and discharges into the environment. 相似文献
17.
The objective of this experiment was to investigate the effects of low-crude protein (CP) diets supplemented with rumen-protected lysine and methionine on growth performance, nitrogen excretion, and carcass traits in Holstein steers. Steers consumed the following diets: (1) 17.2% CP on a dry-matter basis during the early period (from 7 to 10 months of age) and 14.5% CP during the late period (from 10 to 18 months of age; CON, n = 4, initial body weight [BW] 238 kg), and (2) 14.4% CP during the early period and 11.4% CP during the late period (AA, n = 4, initial BW 243 kg). The AA diet contains rumen-protected lysine and methionine. Except for CP intake, feed intake and body weight gain were not affected by dietary CP content. Total nitrogen excretion per metabolic BW tended to be lower (p < .10) in the early period and significantly lower (p < .05) in the late period with decreasing the feed CP content. Plasma urea nitrogen concentrations were lower in AA than CON. Carcass traits and total free amino acid contents of the longissimus thoracis muscle were not affected by dietary CP content. Adding rumen-protected lysine and methionine to a low-CP diet would reduce nitrogen excretion in fattening Holstein steers without affecting productivity. 相似文献
18.
Three multiparous Holstein cows (607 kg of BW) were surgically prepared with an elevated carotid artery and indwelling catheters in the hepatic, portal, and two mesenteric veins to study the effects of methionine supplementation on amino acid metabolism during the last 2 wk of pregnancy. The study began 15 d before the expected calving date. Dietary treatments were Control (1.53 Mcal NE(l)/kg, 15.6% CP, and 40% ruminally undegradable protein) and Control supplemented with 60 g/d of ruminally protected methionine (MET, supplying 39 g/d of DL-methionine and approximately 18 g/d of methionine available for intestinal absorption). Each cow received both dietary treatments in a crossover design. Cows were fed once daily. After 5 d on treatment, a blood flow marker (para-aminohippurate) was infused into a mesenteric vein, and arterial, portal, and hepatic blood samples were obtained at 0, 2, 6, 12, and 18 h after feeding. Net flux of methionine was calculated as the plasma arteriovenous difference multiplied by plasma flow. Dry matter intake (10.8 kg/d) and portal (824 L/h) and hepatic (995 L/h) plasma flows were not affected (P > .10) by treatment. Arterial plasma concentration of methionine was greater (P = .10) with MET (27.67 microM) than with Control (16.42 microM). Net portal absorption of methionine increased (P = .10) with MET (26.2 g/d) compared with Control (9.5 g/d). The net portal methionine flux was negatively correlated (r = -.59; P < .001) with arterial urea concentrations. Net flux of methionine across splanchnic tissues shifted (P = .06) from a net uptake with Control (4 g/d) to a net output with MET (11 g/d). Therefore, MET increased by 15 g/d the methionine supply to the rest of the body. The net uptake of methionine by splanchnic tissues observed with Control indicated a net mobilization of methionine by peripheral tissues. Results indicate that methionine was the limiting amino acid with Control and that MET was beneficial because it increased methionine supply to peripheral tissues and reduced arterial urea concentrations. 相似文献
19.
M. Eklund R. Mosenthin H.‐P. Piepho M. Rademacher 《Journal of animal physiology and animal nutrition》2008,92(5):578-590
The study was carried out to estimate basal ileal endogenous crude protein and amino acid losses (IAALB) and standardized ileal digestibilities (SID) of crude protein (CP) and amino acids (AA) originating from casein in newly weaned pigs from linear relationships between ileal recoveries and dietary intakes of graded levels of CP and AA. A total of 14 (12 + 2 for replacement) 3‐week‐old barrows weighing 5.7 kg was fitted with simple T cannulas at the distal ileum. At 28 days of age, the pigs were randomly allocated to the six experimental diets with two pigs per diet in four weekly repeated measurements. Corn starch‐based diets, containing six graded levels of CP from casein (90, 155, 220, 285, 350, 415 g/kg CP as‐fed basis respectively), were formulated. Titanium dioxide (TiO2) was included as a digestibility marker. Each experimental period consisted of 7 days. Ileal digesta were collected for a total of 24 h during day 6 and 8. Splitting the total range of 90 to 415 g/kg CP into smaller ranges, i.e. from 90 to 220, 220 to 350 or 285 to 415 g/kg CP, provides estimates for CP and AA recoveries which are not significantly different from zero. As a result, dietary CP and AA originating from casein are completely digested and absorbed until the end of the small intestine. In addition, the use of large ranges of dietary CP levels showed that IAALB were affected (p < 0.050) by the dietary CP content. Accepting that ileal recoveries of CP and AA are exclusively of endogenous origin when purified corn starch casein‐based diets are fed, IAALB were estimated as a function of the dietary CP level. There were linear increases (p < 0.050) in IAALB when the dietary CP content was increased from 90 to 415 g/kg. Average IAALB expressed in g/kg dry matter intake (DMI) were 16.3, 0.7, 0.2, 0.9 and 0.2 for CP, lysine, methionine, threonine and tryptophan respectively. These values are in close agreement with IAALB obtained in grower‐finisher pigs. 相似文献
20.
1. A study was conducted to evaluate the effects of two hatching weight (HW) levels and two dietary concentrations of methionine on the growth performance and oxidative status of broilers. Male Arbor Acres chickens were divided into two groups on their HW (low and high HW, H and L). Each HW group was then distributed into two subgroups, of similar HW, receiving either low or high dietary concentrations of methionine (4.9 g methionine/kg, LM; 5.9 g methionine/kg, HM). Thus, all day-old birds were distributed into 4 treatments (H-LM, H-HM, L-LM, L-HM) × 6 replicates × 10 birds for 21 d.
2. Broilers with high HW were heavier than those with low HW during the 21 d assay, which appeared to result from increased body weight gain rather than improved feed conversion efficiency. A higher dietary concentration of methionine (5.9 g/kg) improved growth performance of broilers with low HW in terms of body weight gain and feed conversion ratio.
3. Broilers with different HW had similar antioxidant status both in serum and liver.
4. Broilers given a diet containing 5.9 g/kg methionine had enhanced serum superoxide dismutase (SOD) activity and decreased hepatic malondialdehyde (MDA) content at day 7.
5. Broilers given a diet containing 5.9 g/kg methionine had a higher hepatic reduced glutathione (GSH):glutathione disulphide (GSSG) ratio than those given a diet containing 4.9 g/kg methionine at day 21. High dietary methionine concentration reduced hepatic GSH content and glutathione peroxidase (GPX) activity of broilers with high HW at day 7 and at day 21, respectively, but increased hepatic GSH content of broilers with low HW at day 7.
6. Although broilers with different HW had similar oxidative status as indicated by several parameters in blood and liver, HW can have positive effects on the subsequent growth performance of broilers, and a higher dietary methionine concentration (5.9 g/kg) can improve growth performance and antioxidant status in broilers exhibiting low HW. 相似文献