脂肪细胞膜免疫调控猪生长性能及体脂含量的研究

为了在满足动物营养需要和有效控制疾病的基础上进一步提高动物生产体系的经济效益,人们一直在探索和发展新的促进动物生长和提高胴体品质的技术手段.当认识到激素类制剂的残留和危害后,一种更新的非激素途径-脂肪细胞膜免疫越来越受到人们的重视.它高效安全且作用持久,因而具有广泛的研究和应用前景.     

Growth and carcass characteristics of lambs sired by Dorper and Dorset rams

Growth and carcass merit of Dorset-(DO) and Dorper-sired (DP) lambs were compared over 3 yr in matings with 50% Dorset, 25% Rambouillet, 25% Finnsheep ewes. The DP were slightly lighter (P = 0.09) at birth than the DO lambs. In the first year of the study, DP lambs produced by AI using imported South African sires were heavier than DO lambs when weaned at 60 d of age (21.7 vs. 19.5 kg; P = 0.05). In yr 2 and 3, however, offspring of natural-service Dorper sires produced in the U.S. did not differ in weaning weight from DO lambs (16.9 vs. 17.8 kg; P = 0.02 for breed x year interaction). Lamb survival was also affected by breed x year interaction (P = 0.04). In 2000 and 2001, with 12 to 16% triplet or larger litters, mortality was higher for DP lambs (14.9 vs. 7.7%; P = 0.12). However, in 2002, with approximately 33% triplet or larger litters and with higher mortality levels in all birth types, DP lambs had fewer death losses than did DO lambs (23.2 vs. 36.1%; P = 0.11). No differences between DO and DP lambs were observed in postweaning gain during summer grazing or in drylot in autumn. At chilled carcass weights of approximately 25 kg, DP lambs were somewhat fatter than DO lambs, with greater body wall thickness (P < 0.01; 22 vs. 19 mm) and slightly greater backfat thickness (P = 0.15; 6.4 vs. 5.5 mm) and yield grades (P = 0.15; 2.9 vs. 2.6). The DP lambs also had more desirable leg scores (P = 0.01; 11.6 vs. 10.9) and slightly larger LM area (P = 0.13; 14.1 vs. 13.5 mm2) than did DO lambs, confirming acceptable muscling and conformation in carcasses from Dorper-sired lambs. However, differences were not observed in the percentage of carcass weight in the leg or loin, or in the lean:bone ratio in the dissected leg. Ultrasonic measurements of backfat thickness and LM area taken in live lambs before slaughter were positively associated with direct measures on chilled carcasses with correlations of 0.77 for backfat thickness and 0.51 for LM area.     

Growth and carcass characteristics and serum growth hormone, prolactin and insulin profiles in Debouillet lambs treated with ovine growth hormone and(or) zeranol

Sixteen Debouillet wether lambs (approximately 3 mo old) were placed indoors in 1.5- x 3-m pens (14 h light:10 h dark) 28 d after weaning. Lambs received no implant or a 12-mg zeranol implant on d-2 (eight lambs/group). Two days later (d 0), animals received either 0 or 2.5 mg ovine growth hormone (oGH, eight lambs/group) s.c. on alternate days for 42 d. Animals had ad libitum access to water, salt, mineral and a pelleted alfalfa diet (16% CP). After 42 d, lambs were slaughtered to evaluate carcass traits, organ weights and femur characteristics. Zeranol by oGH interactions were not detected (P greater than .20). Zeranol increased (P less than .05) BW, improved (P less than .05) feed:gain during the first 20 d and increased (P less than .10) feed intake during the last 22 d of the 42-d trial compared with controls. Carcass characteristics were not altered (P greater than .10) by 12 mg zeranol. Serum insulin and prolactin were elevated (P less than .05), but serum GH was not influenced by zeranol compared with controls. Exogenous oGH decreased feed intake (P less than .10) and improved feed:gain (P less than .05) during the initial 20 d compared with controls, but did not influence (P greater than .20) these variables during the last 22 d of the study. Carcass traits were not influenced (P greater than .10) by oGH. Exogenous ovine GH dramatically elevated (P less than .05) serum GH, but did not affect serum insulin or prolactin (P greater than .10).(ABSTRACT TRUNCATED AT 250 WORDS)     

Kidding rates of angora goats passively immunized against estrogens

The objective of this study was to determine the effect of passive immunization against estrone (E1), estradiol (E2) or estrogens (nonspecific; Ens) on ovulation rate and kidding rate in Angora does. On d 0 of the study, Angora does were divided into four treatment groups: 1) passively immunized against E1 (n = 14); 2) passively immunized against E2 (n = 24); 3) passively immunized against Ens (n = 9); and 4) injected with normal goat serum (control; n = 23). Fertile bucks were allowed to mate with the does from d 2 to 44. Immunization treatments did not influence (P greater than .1) percentage of does exhibiting estrus, percentage of does kidding or kid death rate. Ovulation rate was greater (P less than .06) in E2 and Ens immunized does than in control does. Both E2 and Ens treatments resulted in a greater (P less than .05) percentage of does giving birth to twins rather than singles compared with E1 or control treatments (70, 83, 27 and 31% twin births for E2, Ens, E1 and control, respectively). This increase in twin births resulted in kid crops per doe exposed of 142 and 122% for E2 and Ens compared with 100 and 91% for E1 and control treatments (P less than .05 for E2 vs control). These results demonstrate that the incidence of twin births can be increased by passively immunizing does against E2.     

Gonadal function, sexual behavior, feedlot performance, and carcass traits of ram lambs actively immunized against GnRH

The effect of active immunization against GnRH on production, carcass, and behavioral traits was examined in ram lambs fed to a uniform slaughter weight. Lambs (initial BW = 32.6+/-1 kg) were stratified by BW and assigned at random to one of four treatment groups (n = 12 lambs/group). Lambs were untreated, castrated, or actively immunized against GnRH using a GnRH-keyhole limpet hemocyanin conjugate (1 mg) emulsified with either Freund's complete adjuvant (FCA) or another oil-based adjuvant (ISA). Animals were housed individually and slaughtered at 58 kg BW. Immunoneutralization of GnRH reduced (P < .05) testes weight and the concentration of testosterone in serum at slaughter. Suppression of testicular size and function was most clearly evident in animals immunized using FCA. Final anti-GnRH titer was also highest in lambs immunized using FCA. Several measures of sexual behavior (frequency of mounts and ejaculations) were also reduced (P < .05) in animals immunized using FCA. The duration of the feeding period was greater (P < .05) for castrated lambs than for untreated lambs, and intermediate feeding periods were required for FCA and ISA lambs. Average daily gain was greater (P < .05) in untreated than in castrated, FCA, or ISA lambs. Similarly, feed efficiency for untreated lambs was greater (P < .05) than for castrated, FCA, or ISA lambs, but feed efficiency did not differ among castrated, FCA, or ISA lambs. Longissimus muscle area, lean and bone maturity, overall quality, muscling score, flank streaking, and color of fat did not differ among treatments. Intact, FCA, and ISA lambs had more (P < .05) desirable yield grades, less (P < .05) backfat, and less (P < .05) marbling than castrated lambs. In summary, immunization against GnRH decreased testicular weight and reduced (P < .05) feedlot performance and sexual behavior to levels comparable to those of castrated males. Partitioning of nutrients for growth and deposition of fat, however, seems to differ among immunologically castrated and physically castrated lambs. This difference in nutrient partitioning may be due to residual testicular activity in immunized lambs.     

Endocrine,growth, and carcass characteristics of bulls immunized against luteinizing hormone-releasing hormone fusion proteins

This study evaluated the effectiveness of a LHRH fusion protein vaccine on endocrine changes, feedlot performance, and carcass quality of bulls compared with steers and hormone-implanted steers. Crossbred bulls (n = 30; mean weight, 179 +/- 4 kg; mean age, 130 +/- 2 d) were randomly assigned to three treatment groups: 1) castrated (castrated; n = 10); 2) castrated-implanted with trenbolone acetate (implanted; n = 10); and 3) immunized against a cocktail of recombinant fusion proteins, ovalbumin-LHRH-7 and thioredoxin-LHRH-7 (immunized bulls; n = 10). Blood was collected every 2 wk to evaluate antibody and hormone concentrations. Serum LHRH antibodies (P < 0.001) were detected in animals of the immunized group, which had reduced serum LH concentrations (P < 0.001) compared with the castrated groups and serum FSH concentrations, which did not decrease but were significantly different when compared with castrated and implanted animals. Serum testosterone concentrations in the immunized bulls were not different from the two castrated groups (P > 0.05) by d 60 after primary immunization. Initial mean scrotal circumference of the immunized bulls was 18.0 +/- 0.6 cm on d 0 and increased to 22.6 +/- 1.3 cm by d 310. No differences (P > 0.05) in ADG were observed among treatment groups. Immunized animals had an intermediate BW gain (P > 0.05) when compared with the castrates, whereas the castrated groups differed (P < 0.05) from each other. Carcass characteristics were similar (P < 0.05) among the three groups. Vaccinating bulls against a LHRH fusion protein cocktail suppressed LH and testosterone, which led to reduced testicular development and no bullock carcasses. Growth and carcass characteristics of the immunized animals were similar to the steers.     

Growth performance,carcass characteristics,fatty acid composition and CLA concentrations of lambs fed diets supplemented with different oil sources

Quality food for human consumption will always be the aim for animal producers. Quantity and composition of fat deposits (fatty acid profile) strongly influences meat quality in ruminants, especially via increasing conjugated linoleic acid (CLA) concentration, which is known to have beneficial anticarcinogenic, antiatherogenic, antidiabetic and cholesterol reduction properties for human health. Awassi lambs are one of the main and most consumed meat sources in the Middle East area; however, studies addressing the fat content of CLA and methods to enhance its concentrations in this breed are still rare. For this reason, the aim of this study was to evaluate the effect of adding two different oil sources (soybean oil (SBO) and sunflower oil (SFO) at two levels (1.8 and 3%)) on growth performance, carcass characteristics and fatty acid profile of fat in Awassi lambs. Oil supplementation had no effect on growth performance or carcass characteristics, while fatty acid composition changed according to the site of extraction. CLA concentrations were increased in the tail fat deposit, with 1.8% SBO and in intermuscular fat deposit with 3% SFO. Intermuscular fat is the one most naturally consumed by humans, serving to improve food quality.     

Fattening performance, carcass and meat quality characteristics of Kivircik male lambs

The objective of this study was to determine the fattening performance and carcass and meat quality characteristics of Kivircik twin male lambs. Twelve lambs at approximately 5?months of age were subjected to a finishing diet for 60?days. Average live weight of lambs at the beginning and the end of the fattening were 23.14?±?0.84 and 39.0?±?1.01?kg, respectively. Daily live weight gain and feed conversion efficiency were found as 0.265?±?0.007 and 6.14?kg, respectively. Hot carcass weight, cold carcass weight, and dressing percentage were 19.6?±?0.6 and 18.9?±?0.6?kg and 48.1?±?0.3%, respectively. Kidney-pelvic fat weight, internal fat weight, and m. longissimus dorsi area were 0.117?±?0.023 and 0.364?±?0.041?kg and 15.26?±?0.70?cm(2), respectively. The percentages of leg, back loin, forearm, shoulder, neck, flank-chest, kidney-pelvic fat, and internal fat in carcasses of the lambs were found as 34.1?±?0.4%, 19.6?±?0.3%, 21.0?±?0.2%, 7.0?±?0.3%, 10.5?±?0.3%, 7.2?±?0.2%, 1.3?±?0.1%, and 1.8?±?0.1%, respectively. Averages water content, ash, protein content, and fat content of meat samples were 73.4%, 1.0%, 19.5% and 3.6%, respectively. pH and thiobarbituric acid reactive substances values of meat samples were 5.55 and 0.056?±?0.017. L*(lightness), a*(redness), and b*(yellowness) values were recorded as 43.87, 12.69, and 10.22, respectively. Thus, we conclude that fattening performance, carcass, and meat quality of Kivircik lambs are satisfactory levels than that of other native breeds.     

Fatty acid profile and carcass characteristics in castrated and uncastrated hair lambs

The aim of this study was to investigate the effects of castration on carcass characteristics and fatty acid profile of visceral fat and meat from lambs. Eighteen six-month-old Santa Inês male lambs (18.9?±?2.4 kg of body weight (BW)) were used. Animals were assigned to two treatments according to their sexual condition: uncastrated (U) or castrated (C). During a 98-day experimental period, animals were kept on an Andropogon gayanus grass pasture area of 1 ha and supplemented with 200 g/animal/day of concentrate mixture. Water and mineral salt were available ad libitum. The lambs were weighed fortnightly, and at the last day of the trial, they were slaughtered for evaluation of carcass characteristics and fatty acids profile of perirenal fat and longissimus lumborum muscle samples. Castrated lambs showed higher BW than U during most part of the experiment (p?<?0.05). Fat deposition was higher in C lambs as evidenced by their increased carcass fat cover. Meat from U lambs showed lower content of C_16:0 and higher polyunsaturated fatty acids (PUFA) (p?<?0.05) than that from C (U, 14.3 and C, 10.5%). Conjugated linoleic acid (CLA) content was not affected by castration (p?>?0.05) (U, 0.74 and C, 0.76%). The cis-9, cis-12 C_18:2n-6 (U, 10.6 and C, 6.86%) fatty acid and the PUFA:SFA (saturated fatty acids) ratio (U, 0.36 and C, 0.25) were higher in the muscle of U lambs (p?<?0.05), indicating that the meat from U animals may provide more benefits to human health than that of C.

     

抗脂肪细胞膜蛋白抗体对猪内脏器官及红细胞比容的影响

为了研究抗脂肪细胞膜蛋白抗体对猪内脏器官重量及红细胞比容的影响,试验首先制备了兔抗猪脂肪细胞膜蛋白抗体,然后进行动物饲养试验。选择健康、胎次相近、体重为13￣15kg的6周龄云南长撒二元杂交仔猪20头,公母各半,随机分为4组,每组5头。Ⅰ、Ⅱ、Ⅲ组为试验组,腹腔内分别注射抗脂肪细胞膜蛋白抗体10、20和30ml;Ⅳ为对照组,注射20ml非免疫血清。研究结果表明:抗脂肪细胞膜蛋白抗体免疫对心脏和肾脏重量有一定影响,而且随剂量的增加而增大;对红细胞比容有一定的影响,但一般2周后恢复正常。     

Growth performance and carcass characteristics of growing ram lambs fed sweet sorghum bagasse-based complete rations varying in roughage-to-concentrate ratios

Different roughage-to-concentrate ratios of sweet sorghum bagasse (SSB) (a by-product of the biofuel industry)-based complete diets were assessed. Twenty four growing Nellore × Deccani ram lambs aged about 3 months (average body wt., 10.62?±?0.25 kg) were randomly allotted to four complete rations (CR) varying in roughage-to-concentrate ratios viz. 60:40 (CR-I), 50:50 (CR-II), 40:60 (CR-III) and 30:70(CR-IV) for a period of 180 days. The feed intake was comparable among the lambs fed different experimental complete diets. Average daily weight gain (in grams) was 77.31?±?4.90, 81.76?±?5.16, 85.83?±?2.83 and 86.30?±?3.25, and feed conversion ratio (in kilograms of feed per kilogram gain) averaged 11.42?±?0.68, 10.57?±?0.64, 10.17?±?0.37 and 9.96?±?0.38 in ram lambs fed CR-I, CR-II, CR-III and CR-IV rations, respectively. Statistically, differences in daily weight gain and feed conversion ratio among the lambs fed four experimental rations were not significant (P?>?0.05). The cost per kilogram gain was significantly (P?<?0.01) higher in ram lambs fed CR-IV and CR-III rations compared to CR-I ration, and it was comparable between CR-I and CR-II rations. Dressing percentage averaged 44.90?±?0.15, 42.57?±?0.72, 43.67?±?0.16 and 44.42?±?0.76 for the respective diets. No significant difference and trend was observed in preslaughter weight, empty body weight, carcass weights, dressing percentage, wholesale cuts and edible and non-edible portions of experimental animals. Similarly, no significant variation could be seen in bone and meat yield (in per cent) and their ratios in various wholesale cuts among the dietary treatments. The roughage-to-concentrate ratio did not affect the chemical composition of meat; however, the fat content of meat was linearly increased with increase in the proportion of concentrate in the diets. The results of the experiment indicated that SSB can be included at 60 % level in the complete diet for economical mutton production from growing Nellore × Deccani ram lambs.     

Performance and characteristics of carcass and non-carcass components of lambs fed peach-palm by-product

The objective of this study was to evaluate the effects of supplying the by-product of peach-palm (Bactris gasipaes) on performance and characteristics of carcass and non-carcass components of feedlot lambs. Twenty Santa Ines lambs of 150 days average age and 22.4?±?3.4 kg body weight were confined in individual pens. A completely randomized design was utilized with four experimental diets composed of: fresh peach-palm by-product enriched with urea, fresh peach-palm by-product + concentrate, silage of peach-palm by-product + concentrate, and silage of peach-palm by-product enriched with 15 % corn meal + concentrate. Intake was evaluated daily, and at the end of 42 days of experiments, lambs were slaughtered and the characteristics of carcass and non-carcass parts were evaluated. Performance and carcass characteristics showed differences between the animals’ intake of total mixed rations (TMR) and only the diet with roughage. For the lambs that intaked TMR, the form of utilization of roughage (fresh or as silage) affected animal performance but did not change the carcass characteristics. Dry matter intake and feed conversion were influenced by the form of utilization of the silage (with and without additive). Providing fresh by-product plus concentrate improves lamb performance but does not interfere in the carcass characteristics, compared with the use of by-product in the form of silage.     

Effects of cimaterol on energetics and carcass characteristics of Suffolk ewe lambs.

The effects of cimaterol, a beta agonist, on basal metabolic rate, heat increment, maintenance requirements and carcass characteristics were determined using six treated and six control Suffolk ewe lambs. The lambs were fed a pelleted diet (18.7% CP, 2.64 Mcal ME/kg) with or without .5 mg cimaterol/kg BW.75 daily for 70 d. Heat production was monitored for 2 d on each animal at three levels of intake by respiration calorimetry. A 7-d total collection digestion trial was conducted on each animal at both high and low levels of intake. Cimaterol-fed lambs gained more (P less than .05) weight (174 vs 107 g/d) and had a higher (P less than .01) gain/feed ratio (151 vs 90 g/kg) than controls. Cimaterol did not affect diet digestibility or methane production. It reduced (P less than .01) urinary N excretion by 12% and improved (P less than .001) N retention by 18%. Cimaterol also increased carcass weight (26.9 vs 22.1 kg), dressing percentage (57.2 vs 53.9), longissimus muscle area (22.5 vs 15.0 cm2) and leg score (14.3 vs 12.2). Heat production was, on the average, elevated 7 to 10% on d 1 to 4 of cimaterol feeding but reverted to control levels by d 10. Cimaterol did not have any long-term thermogenic effects, either expressed as partial efficiency of ME use for growth (.48 vs .49), as maintenance ME requirements (76 vs 75 kcal/kg BW.75) or as fasting heat production (84 vs 80 kcal/kg BW.75) for treated vs control lambs, respectively. Results indicate little long-term thermogenic effect of cimaterol, even though growth rate and protein deposition were increased.     

Growth, feed intake, carcass characteristics, and eating behavior of feedlot lambs fed high-concentrate diets containing soybean hulls

The objectives of this experiment were to determine the effects of replacing ground corn with soybean hulls (SH) in high-concentrate diets on the growth (56-d period), carcass characteristics, and eating behavior of feedlot lambs. Sixty-four Santa Inês ram lambs (18.3 ± 2.8 kg of BW and 69 ± 5 d of age) were assigned to a randomized complete block design experiment with 8 blocks and 4 diets. The control diet contained 10% coastcross (Cynodon sp.) hay, 70% corn, and no SH (SH0) in the dietary DM. In the remaining diets, SH replaced corn at the rate of 15 (SH15), 30 (SH30), or 45% (SH45) of the original corn concentration, resulting in 0, 10.5, 21.0, or 31.4% SH in the dietary DM. Dry matter intake increased linearly (P < 0.01) when SH replaced ground corn (1.0, 1.0, 1.1, and 1.1 kg/d for SH0, SH15, SH30, and SH45, respectively). There was no effect on ADG of lambs, with values of 276, 278, 282, and 287 g for SH0, SH15, SH30, and SH45, respectively. Feed efficiency decreased linearly (P < 0.01) with SH inclusion. Carcass measures were not affected by SH as a replacement for ground corn. Eating time, expressed as minutes per day and minutes per gram of NDF, showed a quadratic effect (P < 0.05), whereas no effect was observed when expressed as minutes per gram of DM. Rumination, in minutes per day, was not influenced by dietary SH inclusion, but a linear decrease (P < 0.01) was observed when this variable was expressed as minutes per gram of NDF. Soybean hulls can replace up to 45% of the ground corn (31.4% of SH in the dietary DM) in high-concentrate diets fed to feedlot lambs without negative effects on ADG and carcass measures. The linear decrease in feed efficiency (11.6% reduction from SH0 to SH45) suggests that optimal dietary SH inclusion rates should be dictated by the relative costs of SH and corn.     

Associations of polymorphisms of the ovine prion protein gene with growth, carcass, and computerized tomography traits in Scottish Blackface lambs

The objective of this study was to investigate and estimate the associations of the ovine prion protein (PrP) genotypes with a wide range of performance traits in Scottish Blackface lambs. Performance records of up to 7,138 sheep of known PrP genotypes born from 1999 to 2004 in 2 experimental farms were utilized. Performance traits studied were BW at birth, marking (when the sheep were identified with permanent ear tags at an average age of 52 d), and weaning (average age of 107 d); slaughter traits (BW at slaughter, slaughter age, carcass weight, and carcass conformation); ultrasonic muscle and fat depths; and computerized tomography-predicted carcass composition and carcass yield at weaning. Different linear mixed models, including random, direct animal effect, and up to 3 maternal effects (genetic, permanent, and temporary environmental) were used for the different traits. The PrP genotype was included in the model as a fixed effect, along with other fixed factors with significant effects (P < 0.05). Five separate analyses were carried out for each trait, differing in the method of PrP genotypic classification. The first analysis was based on classifying the sheep into categories according to all 9 available PrP genotypes. In the other 4 analyses, sheep were categorized according to the number of each PrP allele carried. Results showed that there were no significant differences between PrP genotypes for any of the performance traits studied when all 9 genotypes were compared (first analysis). Similarly, performance of the lambs did not significantly differ between genotypes with different numbers of ARR copies. However, there were significant variations in a few traits with respect to the number of ARQ, AHQ, and VRQ alleles carried. Heterozygous lambs for the AHQ or the ARQ allele were significantly heavier at some ages than lambs of the other genotypes. Lambs carrying the VRQ allele required approximately 10 d longer finishing time (P = 0.01) and yielded carcasses approximately 0.5 kg heavier (P = 0.03) compared with noncarriers. The few significant associations found do not have a negative influence on performance when selecting against the most susceptible PrP allele (VRQ) or in favor of the most resistant one (ARR). Overall, there were no major associations of PrP genotypes with most lamb performance traits in Scottish Blackface sheep.     

Growth performance and carcass composition of lambs infused for 28 days with a growth hormone-releasing factor analogue.

A human growth hormone-releasing factor analogue, [DesNH2Tyr1,D-Ala2,Ala15]hGRF(1-29)NH2 (GRF-A), was infused s.c. into lambs for 28 d to determine its effects on growth performance and carcass composition. Twenty crossbred wethers weighing 47.0 +/- .5 kg were implanted with 7-d osmotic minipumps at weekly intervals. Minipumps contained either vehicle (dimethyl sulfoxide:H2O, 1:1) or GRF-A, released at a rate of 208 pmol (or .7 micrograms).h-1.kg-1. During the infusion period, plasma GH levels were increased (P less than .01) in GRF-A-treated wethers compared with control wethers (15.0 vs 9.3 ng/ml) and were higher on days that closely followed minipump implantation. Plasma IGF-I and hepatic IGF-I RNA concentrations were similar in lambs of both groups. Analogue treatment improved feed conversion (4.9 vs 5.8 kg dry matter/kg gain, P less than .05), increased average daily gain (.35 vs .30 kg, P = .05) and had no effect on feed intake, wool growth and body, carcass, selected organ and pituitary weights. Carcasses from GRF-A-infused lambs had less adjusted fat depth, a lower percentage of fat and a higher percentage of protein (P less than .05) than carcasses from control lambs. Magnitude of most effects of GRF-A on carcass measurements were correlated with the mean GH level that a lamb had during the infusion period. In conclusion, s.c. infusion of GRF-A improved feed utilization and altered carcass composition of feeder lambs in a relatively short period of time (28 d).