Response of growing goslings to dietary supplementation with methionine and betaine

1. An experiment with a 2 × 3 factorial design with two concentrations of dietary betaine (0 and 600 mg/kg) and three dietary concentrations of methionine (0, 600 and 1200 mg/kg) was conducted using goslings to estimate growth, nutrient utilisation and digestibility of amino acids from 21 to 70 d of age.

2. Three hundred geese were randomised at 18 d of age into 6 groups with 5 replicates per treatment and 10 geese per replicate.

3. Increasing dietary concentrations of methionine gave a linear increase in body weight and average daily gain. The coefficient of crude fat retention increased as dietary methionine increased and there was a significant non-linear response to increasing dietary methionine. Similarly, increasing supplemental methionine gave linear increases in the digestibility of methionine and cysteine.

4. The results of this study indicated that optimal dietary supplementation of methionine could increase growth performance and methionine and cysteine utilisation in growing goslings. Betaine supplementation had no apparent sparing effect on methionine needs for growth performance, but did improve the apparent cysteine digestibility.

     

Assessing the threonine-to-lysine ratio of female broilers from 14 to 28 days of age

Diets for straight-run broiler flocks are often formulated to meet the nutrient requirements of male broilers, assuming this will cover the nutrient needs of the females. Delineating the nutrient needs of female broilers may allow for a more precise formulation and may lead to a reduction in associated feed cost, particularly when feeding sexes separately. A study was designed to simultaneously evaluate the dietary needs of Lys and Thr of a high-yielding female broiler from 14 to 28 d of age. Dose-response diets were accomplished via the diet-dilution technique, and were formulated to provide a range from 0.84 to 1.24% and 0.46% to 0.86% standardized digestible Lys and Thr, respectively. Requirement estimates ranged from 1.06 to 1.11% for standardized digestible Lys, depending on the parameter and the statistical method used, whereas Thr requirement estimates ranged between 0.73 and 0.79%. In addition to the aforementioned requirement estimates, Thr-to-Lys ratios of 69 for BW gain and 70 for FCR were calculated.     

Effects of dietary protein concentration on the response of growing chicks to methionine.

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.     

The effect of herbs and their associated essential oils on performance, dietary digestibility and gut microflora in chickens from 7 to 28 days of age

1. The effect of the dietary inclusion of 5 culinary herbs or their essential oils on the growth, digestibility and intestinal microflora status in female broiler chicks was assessed. From 7 to 28 d of age, either a basal control diet without supplement was given or one of 10 others, consisting of the basal diet with either 10 g/kg herb (thyme, oregano, marjoram, rosemary or yarrow) or 1 g/kg of essential oil. 2. Body mass (BM) and feed consumption (AFC) were measured on a weekly basis and used to calculate chick performance. Total viable counts of lactic acid bacteria, coliforms, anaerobes and Clostridium perfringens were determined at 25 d. Apparent nutrient digestibilities were calculated from the measured values for gross energy, nitrogen (N), dry matter (DM) and organic matter, and sialic acid concentration was also measured. 3. Generally, dietary thyme oil or yarrow herb inclusion had the most positive effects on chick performance, while oregano herb and yarrow oil were the poorest supplements. Only thyme and yarrow in these diets had a different effect when used as a herb or oil on weight gain and BM. 4. Dietary treatment had no effect on the intestinal microflora populations, apparent metabolisable energy (AME) or the calculated coefficients of digestibility. Sialic acid concentration was greatest in the birds given dietary thyme oil, compared with all other treatments except those birds receiving marjoram oil, rosemary herb and the controls. However, less sialic acid was excreted in those birds given diets with oregano or rosemary oils, or oregano herb, than in the controls. 5. Plant extracts in diets may therefore affect chick performance, gut health and endogenous secretions, although the chemical composition of the extract appears to be important in obtaining the optimal effects.     

1～35日龄肉鸡日粮精氨酸与赖氨酸最佳比值的研究

为研究日粮精氨酸水平对1～35日龄雄性科宝肉鸡(Cobb 500)的影响,并运用折线和二次曲线模型进行需要量估计,试验选用1152只1日龄雄性Cobb 500肉鸡,随机分为6组,每组16个重复,每个重复12只鸡。6个处理组精氨酸与赖氨酸比值(Arg/Lys)分别为0.95、1.00、1.05、1.10、1.15和1.20。结果表明:肉鸡前期(0～14 d)随着日粮Arg/Lys比值增加,肉鸡饲料转化率显著改善(线性和二次,P <0.05),Arg/Lys为1.15时比对照组显著降低4.84%。15～35 d,肉鸡的平均日增重随着日粮Arg/Lys呈二次曲线增加(P <0.05),Arg/Lys为1.05组比对照组提高3.33%;饲料转化率呈二次曲线变化,Arg/Lys为1.15组比对照组降低4.4%。整个试验期,Arg/Lys比值为1.05时,肉鸡平均日增重最大,比对照组提高2.57%;Arg/Lys比值为1.15时,饲料转化率最佳,比对照组降低4.6%。从分析模型结果看,基于日增重和饲料转化率,推荐肉鸡日粮精氨酸与赖氨酸适宜比值为1.050～1.134。     

Hourly administration of GnRH to prepubertal gilts: endocrine and ovulatory responses from 70 to 190 days of age.

This study investigated the responsiveness of the pituitary-ovarian axis of prepubertal gilts to hourly injections (i.v.) with GnRH. Six gilts each at 70, 100, 150, and 190 d of age were assigned either to treatment with GnRH or saline. Treatments were given until gilts showed estrus or for 7 d, whichever came first. Hourly pulsing with GnRH resulted in gradually increasing concentrations of estradiol-17 beta (E2), a preovulatory surge of LH, and subsequently increased progesterone (P4) concentrations. The increase in serum P4 was preceded by ovulation and corpora lutea (CL) formation in two gilts 70 d of age and all older gilts. The interval (h) from start of GnRH treatment to peak E2 (88 +/- 3), peak LH (103 +/- 3), and concentrations of P4 greater than or equal to 1 ng/mL (144 +/- 4) did not differ (P greater than .50) for 18 gilts between 100 and 190 d of age. In two ovulating, 70-d-old gilts, the interval from onset of GnRH treatment to peak E2 (171 +/- 6), peak LH (186 +/- 0), and P4 greater than or equal to 1 ng/mL (216 +/- 4) was lengthened (P less than .001). Peak concentrations of E2 (pg/mL) were higher (P less than .01) at 190 d (48 +/- 2) and 150 d (49 +/- 2) than at younger ages and lower (P less than .01) in gilts 70 d of age (31 +/- 1) than in gilts 100 d of age (41 +/- 2). Peak LH (nanograms/milliliter) was higher (P less than .01) in gilts 100 d of age (12.7 +/- 6) than in older gilts. Concentrations of P4 were similar (P greater than .20) for all ovulating gilts. The number of CL (12.7 +/- .7) did not differ (P greater than .20) for 18 gilts 100 d of age or older but was higher (P less than .01) than that (4.5 +/- 1.1) for two gilts 70 d of age. Corresponding endocrine responses or ovulations were not observed in four 70-d-old gilts treated with GnRH or in gilts given saline. These findings indicate that the functional integration of the pituitary-ovarian axis is completed between 70 and 100 d of age. Hourly treatment with GnRH is an adequate stimulus to induce ovulation in prepubertal gilts as early as 70 d of age. Also, the number of follicles reaching ovulatory competency was similar (P greater than .20) in gilts between 100 and 190 d of age, when GnRH was given on a BW basis.     

Growth and plasma metabolites of lambs weaned to legume pasture at 28 days of age

Two trials evaluated the potential for weaning lambs directly onto legume pasture at 28 d of age. Ewes and their twin-reared lambs were placed in paddocks on d 19; ewes were removed on d 28. In Trial 1, 60 lambs were allocated to three treatments: unweaned controls (CON1), lambs weaned onto first-cut alfalfa either without supplementary grain (WOG) or with up to 270 g.hd-1.d-1 supplementary grain (WG). Daily gains for the CON1, WOG and WG lambs were 309, 118 and 159 g for the period from d 28 to 40 (P greater than .05) and 241, 195 and 245 g for the period from d 40 to 56 (P greater than .05), respectively. In Trial 2, 80 lambs were allocated to four treatments: weaning onto first-cut alfalfa (early alfalfa, EA), second-cut alfalfa (late alfalfa, LA) birdsfoot trefoil (BFT) and unweaned controls (CON2, pastured on second-cut alfalfa). Daily gains for CON2 lambs were greater (P less than .05) than gains of EA and LA lambs (327 vs 136 and 136 g, respectively) for d 28 to 40, but not different (P greater than .05) for d 40 to 56 (245, 227 and 195 g, respectively). Gains for BFT lambs were lower (P less than .05) than for CON2 lambs for both periods (122 and 136 g, respectively), and BFT lambs appeared to be unthrifty after weaning. By d 32, weaning caused plasma glucose to decline 16.0 mg/dl and plasma nonesterified fatty acids to increase 365 mu eq/liter from preweaning levels. Hematocrit values ranged from 31 to 35% (Trial 1) and 25 to 29% (Trial 2), suggesting that the weaned lambs did not suffer from dehydration. Crossbred lambs can be weaned at 28 d of age directly onto first-cut or second-cut alfalfa.     

Nutritive value of dry citrus pulp and its effect on performance in geese from 35 to 70 days of age

The study was conducted to determine the chemical composition nutritive value of dried citrus pulp (DCP) and its effect as a feed supplement on the performance of geese. The results of Experiment 1 showed that the DM, GE, CP, EE, CF, NDF, ADF, calcium, and total phosphorous of DCP were 90.75%, 3.60 Mcal/kg, 6.17, 3.51, 15.69, 23.37, 21.49, 3.60, and 0.13%, respectively. The content of methionine, lysine, valine, leucine, isoleucine, threonine, phenylalanine, arginine, histidine, glycine, proline, serine, cystine, alanine, glutamate, tyrosine and aspartate, and tryptophan was 0.02, 0.22, 0.24, 0.33, 0.18, 0.20, 0.22, 0.19, 0.10, 0.25, 0.51, 0.21, 0.02, 0.28, 0.54, 0.15, 0.46, and 0.05%, respectively. In Experiment 2, the digestibility of energy and amino acids of DCP were analyzed using an emptying followed by force-feeding method. The AME of DCP was 2.05 Mcal/kg, and the true total tract digestible methionine, lysine, valine, leucine, isoleucine, threonine, phenylalanine, arginine, histidine, glycine, proline, serine, cystine, alanine, glutamate, tyrosine and aspartate, and tryptophan contained in DCP by geese were 0.01, 0.10, 0.12, 0.19, 0.09, 0.12, 0.14, 0.13, 0.06, 0.14%, 0.42, 0.13, 0.01, 0.15, 0.31, 0.08, 0.28, and 0.03%, respectively. In Experiment 3, 210 35-day-old male Sichuan white geese were randomly allocated to 5 treatments, and each treatment group was fed one of 5 experimental diets containing 0, 4, 8, 12, or 16% DCP until 70 d of age. Geese that were fed diets containing 4% DCP exhibited greater ADG compared to the other 4 groups. Geese fed diets supplemented with 16% DCP had increased ADFI (P < 0.05) and a higher FCR (P < 0.05) than those fed the diet containing zero to 12% DCP. Moreover, inclusion of DCP in the diet did not affect the yields of breast meat, leg meat, subcutaneous fat and skin, and abdominal fat across the 5 treatment groups. In conclusion, DCP appears to be a potential feedstuff for geese, and DCP can be included in diets below 12% without negative effects on growth performance and carcass yield in geese.     

日粮粗纤维水平对35～70 d定安鹅生产性能及器官指数的影响

为研究日粮粗纤维水平对定安鹅生产性能及器官指标的影响,试验选取遗传背景一致、体重相近[(1384.33±0.76)g]的28d定安鹅120只,随机分为3个处理组,每个处理组设4个重复,每个重复10只。分别饲喂粗纤维水平为4.29%、5.29%和6.29%的日粮。试验期为35d。结果表明:(1)5.29%粗纤维组末重和日增重较6.29%粗纤维组分别提高13.57%和27.95%(P<0.05);5.29%粗纤维组采食量比4.29%和6.29%粗纤维组提高5.72%和7.95%(P<0.05);5.29%粗纤维组料重比较6.29%粗纤维组降低16.05%(P<0.05)。(2)5.29%粗纤维组屠宰率、半净膛率、腿肌率和胸肌率分别比4.29%和6.29%粗纤维组分别提高1.64%和2.28%、0.38%和1.03%、0.51%和9.45%、4.31%和6.84%(P>0.05)。腹脂率随着粗纤维水平的提高有下降的趋势(P>0.05)。(3)与4.29%和6.29%粗纤维组相比,5.29%粗纤维组心、肝、胃、肌胃及脾脏指数分别提高5.31%和2.43%、6.15%和5.03%、10.45%和7.29%、11.45%和7.94%、1.65%和2.50%(P>0.05)。综合认为,5.29%粗纤维可使35~70d定安鹅获得较优的生产性能。     

Response to dietary phosphorus deficiency is affected by genetic background in growing pigs

Concern over the environmental effect of P excretion from pig production has led to reduced dietary P supplementation. To examine how genetics influence P utilization, 94 gilts sired by 2 genetic lines (PIC337 and PIC280) were housed individually and fed either a P-adequate diet (PA) or a 20% P-deficient diet (PD) for 14 wk. Initially and monthly, blood samples were collected and BW recorded after an overnight fast. Growth performance and plasma indicators of P status were determined monthly. At the end of the trial, carcass traits, meat quality, bone strength, and ash percentage were determined. Pigs fed the PD diet had decreased (P < 0.05) plasma P concentrations and poorer G:F (P < 0.05) over the length of the trial. After 4 wk on trial, pigs fed the PD diet had increased (P < 0.05) plasma 1,25(OH)(2)D(3) and decreased (P < 0.05) plasma parathyroid hormone compared with those fed the PA diet. At the end of the trial, pigs fed the PD diet had decreased (P < 0.05) BW, HCW, and percentage fat-free lean and tended to have decreased LM area (P = 0.06) and marbling (P = 0.09) and greater (P = 0.12) 10th-rib backfat than pigs fed the PA diet. Additionally, animals fed the PD diet had weaker bones and also decreased (P < 0.05) ash percentage and increased (P < 0.05) concentrations of 1alpha-hydroxylase and parathyroid hormone receptor mRNA in kidney tissue. Regardless of dietary treatment, PIC337-sired pigs consumed more feed and gained more BW than their PIC280-sired counterparts (P < 0.05) during the study. The PIC337-sired pigs also had greater (P < 0.05) HCW, larger (P < 0.01) LM area, and tended to have (P = 0.07) greater dressing percentage. Meat from the PIC337-sired pigs also tended to have greater (P = 0.12) concentrations of lactate but decreased (P = 0.07) concentrations of total glucose units 24 h postslaughter. Although plasma 1,25(OH)(2)D(3) concentrations were elevated (P < 0.05) in all the animals fed the PD diet, this elevation due to P deficiency tended (P = 0.09) to be greater in the PIC337-sired pigs after 12 wk on the treatment. The PIC337-sired pigs had stronger (P < 0.01) bones with greater ash percentage than the PIC280-sired pigs. The difference in the strength of the radii between the PIC337-sired pigs fed the PA and PD diets was greater than their PIC280-sired counterparts, which resulted in sire line x treatment interactions (P < 0.05). These data indicate differing mechanisms of P utilization between these genetic lines. Elucidating these mechanisms may lead to strategies to increase efficiency of growth in a more environmentally friendly manner.     

Electrocardiographic evolution in cats from birth to 30 days of age

Further knowledge of feline physiology and neonatology is needed because the number of cats being kept as pets and used as experimental animals has increased. Few studies have been published on feline sequential electrocardiography. This study was conducted to determine the values of normal waves, complexes, and intervals of the electrocardiogram in clinically healthy feline neonates. Serial electrocardiography was performed in 15 female and 15 male neonates at 30 days of age. Parameters analyzed were heart rate and rhythm, duration and amplitude of electrocardiographic waves, duration of intervals, and the electrical axis of the heart. The results did not show differences between males and females. During the neonates' first 30 days of life, migration of the electrical axis from right to left was observed. There was a progressive increase in the R wave amplitude, while the S wave amplitude showed a progressive decrease. A sinus heart rhythm was predominant in the feline neonates.     

Scanning electron microscopic observations on the intestinal villi in growing White Leghorn and broiler chickens from 1 to 30 days of age

1. To obtain intestinal morphological data demonstrating the faster growth rate in broiler (BR) than in White Leghorn (WL) chickens, villi of the duodenum, jejunum and ileum were examined from 1 to 30 d of age by scanning electron microscopy. 2. At the first day after hatching, villi of each intestinal segment showed a finger-like shape in both breeds. Villi developed to a plate-like shape in the duodenum, a wave-like shape in the jejunum and a tongue-like shape in the ileum at 30 d of age via the common plate-like villi at 10 d of age. The fundamental villous shape and arrangement seem to be accomplished by 10 d of age; two types of obliquely elongated plate-like villi showed a zigzag arrangement, adjoining at an angle of 40 degrees to 60 degrees like an oblique T-shape. It is suggested that such a villous arrangement would be more effective for nutrient absorption by inducing a long zigzag flow of ingesta. 3. Compared with WL, even at the first day after hatching BR had many more developed epithelial cell protrusions over the whole apical surface of the duodenal villi. In WL the protrusions were not so apparent and located only in the central area of the villous tip. Furthermore, at 10 d of age BR showed more developed and larger villi, many wider microvilli at the apical portion of villi and more active extrusions of epithelial cells from the tip of the duodenal and jejunal villi. 4. These morphological characteristics of villi in early life in BR suggest a greater absorptive surface area and a more active intestinal function, permitting the faster growth rate of BR immediately after hatching.     

Effect of dietary fat and cholesterol level on growing pigs selected for three generations for high or low serum cholesterol at age 56 days.

Thirty-six female pigs selected for three generations for high (HS, n = 18) and low (LS, n = 18) serum cholesterol at 56 d of age were used to test the hypothesis that the two populations would respond differently to a high-fat, high-cholesterol diet (HD) and a low-fat, low-cholesterol diet (LD). The animals were four-way crosses (Chester White x Landrace x Large White x Yorkshire). All pigs were fed a standard corn-soybean meal starter diet from weaning (at 4 wk) to 8 wk of age and a grower diet from 8 to 12 wk of age. Initial serum total cholesterol concentration at 12 wk of age was higher (P less than .05) in HS than in LS pigs (94.6 vs 76.9 mg/dL, respectively). The effect of genetic background persisted throughout the 13-wk experiment (25 wk of age); there was no interaction between diet and genetic background in serum total cholesterol (final concentrations were 114.3 mg/dL in HS-HD; 107.0 mg/dL in HS-LD; 105.9 mg/dL in LS-HD; and 89.7 mg/dL LS-LD). Trends over time revealed significant effects of diet (P less than .01) and genetic background (P less than .01) on serum total cholesterol. There was no effect of genetic background on high-density lipoprotein-cholesterol concentration; high-density lipoprotein-cholesterol as a percentage of serum total cholesterol was similar for all groups: 43% for HS-HD, 48% for HS-LD, 42% for LS-HD, and 45% for LS-LD.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pigs weaned from the sow at 10 days of age respond to dietary energy source of manufactured liquid diets and exogenous porcine somatotropin

Previous research indicates that the neonatal pig does not alter feed intake in response to changes in the energy density of manufactured liquid diets. Also, the limited response of IGF-I to exogenous porcine ST (pST) previously observed in young pigs may be influenced by the source of dietary energy. Our objectives were to 1) determine the effect of a high-fat (HF; 25% fat and 4,639 kcal/kg ME; DM basis) or low-fat (LF; 2% fat and 3,481 kcal/kg ME; DM basis) manufactured liquid diet on pig performance; and 2) determine whether the limited response to exogenous pST in young pigs depends on the source of dietary energy. Two replicates of 60 pigs (n = 120; barrows and gilts distributed evenly), with an initial BW of 4,207 +/- 51 g, were weaned from the sow at 10 d of age and used in a randomized complete block design. Pigs were assigned by BW to one of six pens. Diets were formulated to provide a constant lysine:ME ratio and were fed on a pen basis for a duration of 9 d. On d 5, barrows and gilts within a pen were assigned randomly to receive either 0 or 120 microg of pST.kg BW(-1).d(-1) for 4 d. Pigs gained 336 +/- 9 g/d, which resulted in an ending BW of 7,228 +/- 120 g, regardless of dietary treatment (P > 0.15). Pigs fed the LF diet consumed 17% more DM per pen daily than pigs fed the HF diet (2,777 +/- 67 vs. 2,376 +/- 67 g/d, P < 0.01), but calculated ME intake did not differ between dietary treatments (P > 0.20). The G:F was 24% greater in HF- than in LF-fed pigs (P < 0.01). Plasma urea N concentrations were higher in the HF-fed pigs (11.0 +/- 0.6 mg/dL) than in pigs fed the LF diet (6.2 +/- 0.6 mg/dL; P < 0.05). Treatment with pST increased circulating IGF-I (P < 0.01) and decreased PUN (P < 0.01) concentration 32 and 25%, respectively, regardless of dietary treatment (P > 0.30). Circulating leptin averaged 1.8 +/- 0.1 ng/mL and was not affected by dietary treatment (P > 0.35) or pST (P > 0.40). These results suggest that the ST/IGF axis is responsive in the young pig and the increase in circulating IGF-I and growth is independent of the source of dietary energy. Also, young pigs respond to a lower energy density liquid diet with increased feed intake, without altering growth performance, apparently utilizing a mechanism other than circulating leptin.