Meat quality of fully or partly outdoor reared pigs in organic production

Abstract

Outdoor production on pasture is considered an option in organic pig production. The aim of the present trial was to study the influence of feeding strategies combining outdoor and indoor rearing on pig meat quality. The experiment was carried out with 245 pigs in 5 replicates, and commenced following weaning at day 52. Five treatments were compared: 1) pigs fed ad libitum and reared indoors with access to an outdoor concrete area (In-A); 2) pigs fed restrictively on pasture until 40 kg body weight and then kept indoors with access to an outdoor concrete area and fed ad libitum until slaughter (In-40A); 3) pigs fed restrictively on pasture until 80 kg body weight and then kept indoors with access to an outdoor concrete area and fed ad libitum until slaughter (In-80A); 4) pigs reared on pasture and fed restrictively during the whole period of growth (Out-R); and 5) pigs reared on pasture and fed ad libitum during the whole period of growth (Out-A). All pigs had free access to roughage (clover-grass silage/fresh clover grass). Restrictive feeding in the weight range from weaning to 40 kg body weight (In-40A) resulted in a reduced daily gain; however, following transfer to indoor facilities and ad libitum feeding these pigs compensated in growth and the overall daily gain did not differ from the In-A control pigs. Pigs fed restrictively from weaning to 80 kg body weight were unable to compensate completely following transfer to indoor facilities. Out-R pigs had the lowest overall daily gain, while In-A pigs and Out-A pigs had similar daily gain. Meat quality assessments were performed on longissimus dorsi (LD) samples from a subsample of 100 pigs (2 castrates and 2 female pigs from each treatment in each replicate). Compared to meat from either ad libitum treatments (In-A and Out-A), meat from Out-R and In-80A pigs was less red due to a lower pigmentation, and had a higher ratio of polyunsaturated:saturated fatty acids. In addition, Out-R female pigs had numerically (6–10 Newton) higher shear force than In-A and Out-A. Treatments did not affect the concentration of α-tocopherol of meat. Introducing a finishing period with free access to concentrates following 40 kg body weight until slaughter prevented the deterioration in meat quality. However, a finishing period following 80 kg body weight was not sufficient. In conclusion, ad libitum feeding in the organic production system gave superior meat quality compared to a restrictive feeding strategy. However, including a finishing period indoors with ad libitum feeding of concentrates may prevent the detrimental effect of restrictive feeding on meat quality.     

Effects of temperature and level of feeding during rearing on carcass and reproductive traits in pigs

A total of 315 crossbred females (gilts) ranging in weight from 14 to 68 kg was split between pole-type and a closed piggery (cold and moderate environments, respectively One third of the pigs in each piggery was fed a growing ration ad libitum, the remaining pigs were restrictively fed 80% of the amount consumed by the first group. Data on ultrasonic backfat probe, estimated market index, and age were taken on the pigs at 90 kg live weight. Results indicated that the effect of environmental temperature was very small on backfat thickness and carcass index, but was significant on age. The pigs fed ad libitum had 10.2% thicker backfat, were 4 points inferior in index, but were 13 days younger at 90 kg (P < 0.01) than those restrictively fed. When the gilts exhibited their first oestrus after 90 kg live weight, half of the pigs restrictively fed were flushed by feeding them ad libitum for one oestrus cycle. All gilts were bred at the second oestrus. The gilts raised in a cold environment were 4 kg lighter, farrowed litters 0.2 larger and 0.5 kg heavier than those raised in the moderate environment. Gilts restrictively fed, then flushed gained 3 kg on flushing and farrowed litters averaging 10.7 pigs, 0.2 and 0.8 pigs larger than those of the gilts fed ad libitum and not flushed respectively. Significant differences between crosses were observed in all the traits studied except gestation length and litter size. There was little effect on the different traits of the initial weight at which the gilts were exposed to the treatment.     

Muscle protein degradation in bull calves with compensatory growth

Twelve 5-month-old bull calves were allocated to two feeding strategies: AA, 6 calves were fed ad libitum 34 weeks; and RA, 6 calves were fed restrictively for 14 weeks with an intake of 50% of the metabolic energy and protein eaten by the AA calves, followed by ad libitum feeding for 20 weeks. At the end of the 14-week restriction period, and after 2, 5, 8, 11, 14 and 17 weeks of re-alimentation, urine, blood and muscle biopsy samples from M. longissimus dorsi (LD) were collected. The urine was analysed for 3-methylhistidine for determination of the fractional breakdown rate of muscle protein (FBR). The FBR was depressed during restricted feeding (1.4 versus 2.0%/day; P = 0.05), however, during re-alimentation where the calves exerted compensatory growth, the FBR increased and reached a maximum after 5 weeks into this period (3.1 versus 1.9%/day; P < 0.001). The maximal FBR in the RA calves coincided with a maximum concentration of RNA and DNA in LD, and a maximal fractional rate of growth. The activity of μ-calpain in LD and the concentration of IGF-I in serum were decreased at the end of the restriction period but increased as soon as energy was offered ad libitum. The results support the hypothesis that muscle protein turnover is affected by a restriction/re-alimentation feeding strategy, and that muscle protein degradation reaches a maximum during the re-alimentation period, which exceeds that of control animals.     

Dietary-induced changes of muscle growth rate in pigs: effects on in vivo and postmortem muscle proteolysis and meat quality

The effects of various growth rates in pigs induced by four different feeding strategies on the activity of the calpain system and on postmortem (PM) muscle proteolysis and tenderness development were studied. An increased growth rate may be caused by an increased protein turnover, which results in up-regulated levels of proteolytic enzymes in vivo that, in turn, possibly will affect PM tenderness development. It can be hypothesized that increased proteolytic activity pre-slaughter will increase the PM tenderization rate. From postnatal d 28 to d 90 (phase 1) the pigs were divided into two groups, given either ad libitum (A) or restricted (R, 60% of ad libitum) access to feed. The two groups were then divided into two subgroups, given either restricted or ad libitum access to feed from d 91 to slaughter at d 165 (phase 2). Measurements of the activity of mu-calpain, m-calpain, and calpastatin; concentrations of total collagen and the percent of soluble collagen; and RNA, DNA, and elongation factor-2 where made at slaugther. Myofibrillar fragmentation index (MFI) was determined at slaughter and 24 h PM. Warner-Braztler shear force was determined 1 d and 4 d PM. Pigs fed restricted diets in phase 1 and fed ad libitum in phase 2 (RA pigs) had increased growth rates in the last phase compared to pigs fed ad libitum during both phase 1 and phase 2 (AA pigs). The increased growth rate (compensatory growth) was followed by an increased proteolytic potential (mu-calpain:calpastatin ratio), increased MFI values, and higher tenderization rates. There was a positive correlation between the activities of m-calpain and growth rates (r = 0.35, P = 0.03), and between RNA levels and growth rates (r = 0.43, P = 0.006). The proposed hypothesis is largely supported by the results. The activities of both mu- and m-calpain at slaughter were highest in fast-growing pigs. The calpain activity was highest in RA pigs, which in turn also had the fastest growth rates prior tslaughter among the four groups. This implies that the synthesis of these enzymes was up-regulated during the second feeding period to a larger extent in RA pigs. The proteolytic potential and the MFI values indicate that the up-regulated in vivo calpain activity had an effect on PM protein degradation, which also is supported by the higher tenderization rate in RA pigs.     

饲喂模式对猪生长性能、养分消化率和肠道微生物组成的影响

本试验旨在探究不同饲喂模式对猪生长性能、养分消化率和肠道微生物组成的影响。选择120头平均初始体重(26.0±0.4)kg的生长猪(公、母各半),按体重和性别随机分为自由采食组(FA)和限制饲喂频率组(每天饲喂3次,M3),每个处理10个重复,每个重复6头猪,试验期共28 d。结果表明:M3组平均日采食量和耗料增重比均显著低于FA组(P<0.05);饲喂模式的改变对养分表观全肠道消化率无显著影响(P>0.05);M3组血浆尿素氮和游离脂肪酸水平显著低于FA组(P<0.05),而胰岛素水平显著高于FA组(P<0.05);饲喂模式对猪粪便微生物组成有一定影响,在门水平上,M3组拟杆菌门丰度显著低于FA组(P<0.05),柔膜菌门和疣微菌门丰度显著高于FA组(P<0.05);在属水平上,M3组Prevotellaceae_UCG-003、Ruminococcaceae_UCG-010、Ruminococcaceae_NK4A214_group、Rikenellaceae_RC9_gut_group和Coprostanoligenes_group的丰度显著高于FA组(P <0.05),而Selenomonas、Roseburia、Prevotella_2、Prevotella_7、Prevotella_9、Anaerovibrio和Alloprevotella的丰度显著低于FA组(P<0.05)。综上,饲喂模式对生长猪养分消化率无显著影响,限制饲喂频率可改变肠道微生物组成并改善生长猪饲料报酬。     

Effect of Feeding Environment on Performance,Injuries and Behaviour in Growing-finishing Pigs: Group-Based Studies

Ten batches of pigs (608 pigs) were used in this investigation (live weight interval 20-120 kg). Four different feeding systems were tested: one dry feeder, four dry feeders, trough feeding or one wet/dry feeder per pen of 16 pigs, respectively. The one dry feeder treatment led to an increase in skin injuries, a more spread feed intake pattern, an increased variation in carcass meat percentage and an increased variation in daily weight gain (DWG) when the pigs were restrictively fed, compared with observations for the pigs in the four dry feeders treatment. The effect of a reduced number of feeding places was most pronounced when the pigs were fed restrictively. Besides the possible negative financial effects for pig producers, these findings indicated that competition for feed impaired the well-being of the pigs. Pigs fed in a trough had a lower DWG and higher feed conversion ratio than did those fed using four dry feeders, probably due to feed spillage and the different feed intake pattern. Giving pigs the possibility of adding water to the feed increased the daily feed intake when feeding ad libitum, resulting in a higher DWG. It also reduced the negative effects of competition on performance, but not the negative effects on skin injuries.     

Increased maternal nutrition of sows has no beneficial effects on muscle fiber number or postnatal growth and has no impact on the meat quality of the offspring

The objective of this study was to examine how increased feed intake of the sow during early to mid-gestation affects sow performance and the muscle fiber number, performance, and technological meat quality of the offspring. Thirty-nine pregnant sows (Landrace x Large White sows mated to Landrace or Large White boars) in their fourth parity were assigned to one of three treatments: 1) the sows were either fed restrictively (control = 15 MJ of NE/d from d 1 to 90, then 24 MJ of NE/d from d 91 to 112, and again 15 MJ of NE/d from d 113 to 115 of gestation); 2) fed ad libitum from d 25 to 50 (A25-50); or 3) ad libitum from d 25 to 70 (A25-70) and as control in the remaining periods. The offspring were weaned at 4 wk of age and had free access to feed from 2 wk of age until slaughter. They were slaughtered litterwise at an average body weight of 104 +/- 14 kg. Estimates for total, primary (P-), and secondary (S-) muscle fiber number; muscle fiber area; and DNA and RNA content were analyzed in semitendinosus muscle (ST) samples from the heaviest, middle, and lightest weight (LW) pigs of each sex within litter selected at slaughter. Technological meat quality traits (pH at 24 h postmortem, drip loss, Minolta color, and pigment) were analyzed in longissimus dorsi muscle. Fiber number, fiber area, and concentrations and content of DNA and RNA of the offspring were not significantly affected by increased maternal nutrition. The ST muscle weight was lower in offspring from A25-50 than control sows (P = 0.019). Average daily gain, carcass weight, and the muscle deposition rate also were numerically lower for A25-50 than control and A25-70 pigs. An interaction between treatment and pig weight was found for muscle deposition rate (P = 0.006), in that LW pigs from treatment A25-50 had a lower deposition rate than LW pigs from control. We found no effect of treatment on the meat quality traits in the offspring. Also, barrows had a higher (P < 0.05) number of P-fibers, higher daily gain, and carcass weight than female pigs. No differences were found on any meat quality traits between sexes. Thus, ad libitum feeding of pregnant sows from d 25 to 50 or d 25 to 70 of gestation did not have any beneficial effect on muscle fiber number and area in the offspring. It seems that maternal ad libitum feeding from d 25 to 50 in gestation had a negative effect on postnatal muscle growth, with especially the LW pigs being affected.     

EFFECT OF FEEDING REGIMEN ON GASTRIC ULCERATION OF THE PARS OESOPHAGEA OF INTENSIVELY RAISED PIGS

Three groups of pigs (total 23 pigs) were fed ad libitum from weaning until market weight and these were compared with three groups of pigs (total 26 pigs) fed ad libitum until 12 weeks of age, and then fed on a restricted regimen (twice per day) until marketed.
There was a significant difference in degree of ulceration between the two feeding regimens; those pigs fed ad libitum had the most severe gastric ulcers.
The pigs fed ad libitum , had significantly less agonistic interactions per minute than did the restricted fed pigs. Growth rates of the pigs from weaning to market weight did not differ significantly in the two regimens, although the average pig on ad libitum feeding consumed 182.9 kg, and the restricted fed pigs ate 148.2 kg per pig.     

The effect of two different feed levels on the development of the reproductive organs in boars.

The aim of the present investigation was to study the development of the reproductive organs in boars fed restrictively and fed ad libitum. A total of 120 boars were purchased by the experimental station at 20 kg live weight. Three groups of 4 litter mates were selected after each of 10 A.I. boars (7 Swedish Landrace and 3 Swedish Yorkshire). The dams were unselected sows from pigletproducing herds. Two boar pigs from each litter were allocated at random among 2 treatment groups. One group ( = N) was fed restrictively and the other group (=A) ad libitum. The boars were slaughtered at 90 kg or at 120 kg live weight. The reproductive organs were removed at slaughter and examined.The ad libitum fed boars were about 2 weeks younger at slaughter than those fed restrictively (16.5 and 13.7 days respectively for the 2 weight classes). The weights of the testes were somewhat higher for ad libitum fed than for restrictively fed boars. Out of 94 examined pairs of testes, epididymides, seminal vesicles and bulbo-urethral glands, the left was heavier than the right in 68%, 62%, 48%, and 36%, respectively. Fewer (4/23) ad libitum fed than restrictively fed boars (9/26) had reached puberty at 90 kg live weight. Age at puberty thus seems to be less variable than body size in boars.     

Compensatory growth improves meat tenderness in gilts but not in barrows

Compensatory growth is a phenomenon observed in pigs given free access to feed following a period of restricted feeding that results in increased growth rates. Compensatory growth is believed to increase protein turnover and thereby the proteolytic potential at the time of slaughter, leading to faster tenderization rates of meat. Nine litters of three gilts and three barrows were allocated within litter and gender to three dietary treatment groups. Pigs had ad libitum access to feed from d 28 to slaughter at d 140 (ALA) or were restricted to 69% ad libitum from d 28 to d 80 or 90, and then given ad libitum access to the diet until slaughter at d 140 (RA80 and RA90, respectively). Pigs in the RA80 and RA90 treatment groups had a 9.7% higher (P < or = 0.001) fractional growth rate in the second feeding period than those in the ALA group. Growth rate was correlated to the activity of m-calpain (r = 0.37; P < or = 0.01), beta-glucuronidase (r = 0.48; P < or = 0.001), and cathepsins B (r = 0.47; P < or = 0.001) and B+L (r = 0.31; P < or = 0.04). The LM of RA80-gilts received higher tenderness scores than the LM of ALA gilts, but tenderness scores were similar among barrows regardless of treatment (gender x treatment; P = 0.02). Conversely, tenderness scores were higher for the biceps femoris of ALA barrows than either ALA gilts or RA90 barrows (gender x treatment; P = 0.02). Desmin and troponin-T degradation, as well as myofibrillar fragmentation index, of the LM were not (P > or = 0.24) affected by treatment. No dietary treatment effects were observed on the activities of mu-calpain (P = 0.15), m-calpain (P = 0.74), or calpastatin (P = 0.91) at slaughter. The cathepsin inhibitors, cystatins, tended to be increased (P = 0.06) in RA80 and RA90 pigs. Sarcomere length was longer (P = 0.003) in the LM of gilts than barrows. Barrows in the RA80 group had lower i.m. fat concentrations than ALA; however, no differences were found in the LM of gilts (gender x treatment; P = 0.03). The underlying hypothesis that compensatory growth leads to an increased proteolytic potential at the time of slaughter could not be verified in this study.     

Carcass dissection and commercial meat yield in Piemontese and Belgian Blue double-muscled young bulls

To study the differences in meat yield in hypertrophied cattle, a commercial dissection trial was carried out on 48 carcasses obtained from 24 Piemontese (P: 12 reared with a restricted feeding, P-R, and 12 fed ad libitum, P-L), and 24 Belgian Blue (B: 12 reared with a restricted feeding, BB-R, and 12 fed ad libitum, BB-L) young bulls. The animals were reared under the same environmental condition and slaughtered at the same age and fattening degree. During commercial dissection, the weights of the retail cuts were recorded. Three fore-quarter meat cuts were heavier in P than in BB, while nine meat cuts (two from fore-quarter and seven from hind-quarter), hind-quarter meat and prime quality meat were heavier in BB than in P. Fat weight was higher in BB than in P, whereas meat production as a percentage of carcass side weight was higher in P than in BB. Only one hind-quarter meat cut was heavier in the ad libitum (L) than in the restricted (R) group, whereas meat yield was higher in R than in L. In comparing the meat yield in carcass sides of P-R, P-L, BB-R and BB-L fed young bulls, four meat cuts (one from fore-quarter and three from hind-quarter), hind-quarter, prime quality and 3rd quality meat were heavier in BB-L (P ≤ 0.05), while one shoulder cut and fore-quarter were heavier in P-R group.     

Performance,carcass and technological meat quality of pigs in indoor and outdoor production systems

Abstract

This study aimed to compare different production systems, i.e., the combined effect of outdoor and indoor rearing of pigs and organic diets fed ad libitum or restrictively. Furthermore, the suitability of two breed crosses for outdoor rearing was studied. The effects on performance, carcass and technological quality traits were investigated. During two years, 240 pigs of Duroc x Large White (D*LW) and Swedish Landrace x Large White (L*LW) were allocated to three production systems: 1) Pigs kept outdoors, fed an organic diluted diet (20% alfalfa roughage) ad libitum; 2) Pigs kept outdoors, strategically fed a diluted organic diet up to a live weight of approximately 80 kg and thereafter an undiluted organic diet ad libitum; 3) Pigs kept indoors, fed an undiluted organic diet restrictively. For outdoor pigs, strategic feeding increased daily weight gain and backfat thickness, compared with feeding a diluted diet throughout (p≤0.01). L*LW pigs in both outdoor systems grew slower than in the indoor system (p≤0.001), whereas for D*LW pigs only outdoor pigs fed the diluted diet had a slower growth rate. Outdoor pigs had lower dressing percentage than indoor pigs. Glycogen content and L* values in M. longissimus dorsi were higher, whereas b* values were lower in meat from pigs in the indoor system. D*LW pigs had higher water-holding capacity (lower drip, thawing and cooking losses), lower shear force and higher intramuscular fat content compared with L*LW pigs.     

The effects of undernutrition of suckled pigs on subsequent growth and body composition after nutritional rehabilitation

The effect of nutritional restriction and rehabilitation imposed between 5 and 35 d and 35 and 166 d of age, respectively, on body and tissue growth were investigated in 96 Yorkshire pigs from 12 litters. One-half of the pigs were allowed to suckle continuously until weaning (fully fed, FF); the remainder were removed from the sow for 16 h of each 24 h period (1600 to 0800 h), during which time they received only water (restricted feeding, RF). All pigs were fed ad libitum from 35 d of age. Although significantly lower body and tissue (liver, kidney and gastrocnemius muscle) weights were observed in the RF pigs at 35 and 70 d of age, by 166 d, because of compensatory growth between 35 and 166 d, the difference in body and muscle weights between the two groups of pigs (RF and FF) was reduced to 5%, but the difference in kidney and liver weight remained as high as 15 and 9%, respectively. Total DNA, RNA and protein in the tissues examined were also lower in the RF pigs at 35 and 70 d of age, but increased after ad libitum feeding to more than 90% of the corresponding value in the FF pigs by the time they reached 166 d of age. The results of these measurements and the comparison of the protein: DNA ratios of the tissues indicated that growth retardation in the RF pigs was associated with reduced cell proliferation in liver and kidney and nuclear proliferation in muscle rather than any decrease in cell (or fiber) volume. Percentage of fat was lower while percentage of protein was higher (on a dry matter basis) in the RF pigs than in the FF pigs at 35 d of age. No significant difference in fat and protein content in the carcasses between the RF and FF pigs at 70 or 166 d of age or 90 kg body weight was noted. The carcass of intact males had more protein and less fat than that of females.     

Growth performance, diet apparent digestibility, and plasma metabolite concentrations of barrows fed corn-soybean meal diets or low-protein, amino acid-supplemented diets at different feeding level

Two experiments, each with 36 barrows with high-lean-gain potential, were conducted to evaluate apparent nutrient digestibilities and performance and plasma metabolites of pigs fed corn-soybean meal diets (CONTROL) and low-protein diets. The low-protein diets were supplemented with crystalline lysine, threonine, tryptophan, and methionine either on an ideal protein basis (IDEAL) or in a pattern similar to that of the control diet (AACON). Amino acids were added on a true ileally digestible basis. The initial and final BW were, respectively, 31.5 and 82.3 kg in Exp. 1 and 32.7 and 57.1 kg in Exp. 2. In Exp. 1, the CONTROL and IDEAL diets were offered on an ad libitum basis or by feeding 90 or 80% of ad libitum intake. Pigs were fed for 55 d. In Exp. 2, the CONTROL, IDEAL, and AACON diets were offered on an ad libitum basis or by feeding 80% of the ad libitum intake. Pigs were fed for 27 d. Pigs fed the CONTROL diet had greater (P < 0.05) ADG and feed efficiency (G/F) than pigs fed the IDEAL (Exp. 1 and 2) and AACON diets (Exp. 2). As the level of feed intake decreased, ADG decreased (P < 0.05), but G/F tended to improve (P < 0.10) for pigs fed 90% of ad libitum in Exp. 1 and for pigs fed 80% of ad libitum in Exp. 2. In Exp. 1, the apparent total tract digestibilities of DM and energy were greater (P < 0.01) for pigs fed the IDEAL diet than for pigs fed the CONTROL diet. In Exp. 2, the apparent total tract digestibility of protein was greatest in pigs fed the CONTROL diet (P < 0.05) and was greater (P < 0.05) in pigs fed the AACON diet than in pigs fed the IDEAL diet. Plasma urea concentrations were lower in pigs fed the IDEAL diet than in pigs fed the CONTROL diet, regardless of feeding level. For pigs fed the CONTROL diet, plasma urea concentrations were lower when feed intake was 80% of ad libitum (diet level, P < 0.01). In summary, pigs fed the IDEAL and the AACON diets gained less and had lower plasma urea concentrations than pigs fed the CONTROL diet. Based on these data, it seems that the growth potential of pigs fed the IDEAL and AACON diets may have been limited by a deficiency of lysine, threonine, and(or) tryptophan and that the amino acid pattern(s) used was not ideal for these pigs.     

饲喂模式对生长育肥猪胴体品质和脂质代谢的影响

本试验旨在研究饲喂模式对生长育肥猪生长性能、胴体品质和脂质代谢的影响。试验选择48头平均初始体重为(61.4±2.5)kg的杜×长×大三元杂交去势公猪,根据体重按随机区组设计分到自由采食组(自由采食)和限制饲喂频率组(每天饲喂2次)。每个处理8个重复,每个重复3头猪。结果表明:限制饲喂频率组的平均日采食量(ADFI)、平均日增重(ADG)、胴体重、屠宰率和平均背膘厚均显著低于自由采食组(P0.05);饲喂模式对猪肉品质相关指标无显著影响(P0.10);限制饲喂频率组脂肪组织中苹果酸酶(ME)和脂肪酸合成酶(FAS)的活力显著低于自由采食组(P0.05);限制饲喂频率组脂肪组织中FAS和过氧化物酶体增生物激活受体γ(PPARγ)的m RNA表达量显著低于自由采食组(P0.05)。综上分析,限制饲喂频率降低了生长育肥猪的生长性能、胴体品质和脂肪沉积,但对肉品质无显著影响,其中限制饲喂频率主要是通过降低脂肪合成减少脂质沉积。     

分娩后不同饲喂模式对泌乳母猪生产性能、乳成分和生理代谢的影响

本试验旨在研究母猪分娩后3种饲喂模式(产后不限饲、限饲3 d和限饲7 d后自由采食)对泌乳母猪生产性能、乳成分和生理代谢的影响。挑选遗传背景一致、体况和健康良好、分娩日期接近的3~6胎次丹系长×大母猪45头,分娩后根据体重、背膘厚度和胎次随机均分成3个组,每组15个重复,每个重复1头。3组母猪饲喂相同的泌乳饲粮,执行对应的饲喂模式:不限饲组(FR0组)分娩后立即自由采食;限饲3 d组(FR3组)分娩后前3 d逐步增加饲喂量,之后自由采食;限饲7 d组(FR7组)分娩后前7 d逐步增加饲喂量,之后自由采食。分娩后第22天仔猪断奶,试验结束。结果表明:1)FR0组和FR3组第1周和泌乳期母猪采食量以及哺乳期仔猪平均日增重(ADG)显著高于FR7组(P<0.05);FR0组泌乳期母猪背膘厚度和体重损失显著低于FR3组和FR7组(P<0.05);FR0组第1周和泌乳期母猪采食量显著高于FR3组(P<0.05),但哺乳期仔猪ADG的差异没有达到显著水平(P>0.05)。2)各组间乳成分没有显著差异(P>0.05)。3)与FR7组相比,FR0组和FR3组血浆中催乳素、胃饥饿素和瘦素含量显著增加(P<0.05),胰岛素和皮质醇含量显著降低(P<0.05);FR0组血浆尿素氮含量显著高于FR7组(P<0.05),与FR3组差异不显著(P>0.05);各组间血浆葡萄糖和甘油三酯含量没有显著差异(P>0.05)。由此可见,分娩后饲喂模式会影响泌乳母猪的采食量、背膘厚度和体重损失以及机体生理代谢状况。本试验条件下,现代高产瘦肉型母猪产后不限饲和缩短限饲天数(限饲3 d)都可以提高泌乳母猪的采食量和泌乳性能,其中不限饲是适宜的饲喂模式。     

饲粮能氨水平对不同品种猪肉质性状及相关基因表达的影响

本试验旨在研究饲粮能氮水平对不同品种猪肉质性状以及肌纤维类型和细胞因子相关基因表达的影响.选取巴马香猪和长白猪共96头(48头/品种),随机分为4组(每组24头猪),分别为长白猪饲喂NRC饲粮组、长白猪饲喂我国地方猪标准(GB)饲粮组、巴马香猪饲喂NRC饲粮组、巴马香猪饲喂GB饲粮组.试验从5周龄开始,至出栏时结束.分别于保育期、生长期和肥育期末,每组选择8头体况相近猪只屠宰,采集肌肉样品分析.结果表明:生长阶段显著影响了试验猪背最长肌熟肉率和肌球蛋白重链(MyHC)Ⅱx、MyHCⅡ易及白细胞介素-15(IL-15)mRNA表达水平(P<0.05),且随生长阶段呈增加趋势;与长白猪相比,巴马香猪的背最长肌熟肉率、MyHC Ⅰ mRNA表达水平显著升高(P<0.05),而滴水损失显著降低(P<0.05);与NRC饲粮相比,GB饲粮显著提高了生长期长白猪和巴马香猪的pH45 min(P<0.05),显著上调了保育期和肥育期猪背最长肌MyHC Ⅰ mRNA表达水平(P<0.05);与GB饲粮相比,NRC饲粮显著上调了生长期猪背最长肌MyHC Ⅰ mRNA表达水平(P<0.05).由此可见,品种和生长阶段均可显著影响肉质性状及相关基因的表达,饲粮能氮水平则主要通过与生长阶段产生互作效应影响肉质性状及肌纤维类型相关基因的表达.     

Compensatory growth response in pigs: effects on growth performance, composition of weight gain at carcass and muscle levels, and meat quality

A restriction/realimentation feeding strategy was applied to pigs to increase the age at market weight and final ADG, modify protein and lipid deposition rates at carcass and muscle levels, and thereby improve eating quality of the pork. A total of 126 Duroc x (Large White x Landrace) pigs (females and castrated males) were used. At the average BW of 30 kg, within litter and sex, pairs of littermates (blocked by BW) were randomly assigned to ad libitum (AL) feeding during growing (30 to 70 kg of BW) and finishing (70 to 110 kg of BW) periods (AL, n = 56), or restricted feeding at 65% of the ADFI of the AL pigs, on a BW basis, during the growing period and AL feeding during finishing (compensatory growth, CG; n = 56). In each feeding regimen, 15 pigs were slaughtered at 70 kg of BW, and 41 pigs were slaughtered at 110 kg of BW. Additionally, 14 pigs were slaughtered at 30 kg of BW to calculate tissue deposition rates. The CG pigs showed decreased ADG (-35%, P = 0.001) during growing but increased ADG (+13%, P = 0.001) during finishing (i.e., compensatory growth) due to greater (P = 0.001) ADFI and G:F. Hence, CG pigs were 19 d older at 110 kg of BW than AL pigs. The CG pigs were leaner at 70 kg of BW than AL (e.g., 11.7 vs. 13.5 mm of average backfat thickness for CG and AL pigs, respectively, P = 0.023), whereas the differences were reduced at 110 kg of BW (20.6 vs. 21.0 mm of average backfat thickness for CG and AL pigs, respectively, P = 0.536). At 70 kg of BW, intramuscular fat (IMF) content of LM did not differ between CG and AL pigs (1.25 vs. 1.49%, respectively, P = 0.118), whereas CG pigs had less IMF in LM at 110 kg of BW (2.19 vs. 2.53% for CG and AL pigs, respectively, P = 0.034). Feeding regimen influenced the composition of weight gain. From 30 to 70 kg of BW, feed restriction reduced (P = 0.001) lean and adipose tissue deposition at the carcass level and protein and lipid deposition at the muscle level. From 70 to 110 kg of BW, the CG feeding strategy increased (P = 0.016) deposition of adipose but not of lean tissue at the carcass level. However, lipid and protein deposition at the muscle level were not affected. Thus, realimentation promoted deposition of subcutaneous fat over IMF. Feeding regimen hardly affected technological meat quality at 110 kg of BW. The CG feeding strategy decreased (P = 0.014) the meat juiciness score in relation to the decreased IMF but did not influence other sensory traits. Elevated IMF content and improved pork quality might be achieved by modifying the onset or duration of the restriction and realimentation periods.     

Effects of Cereal Disintegration Method,Feeding Method and Straw as Bedding on Stomach Characteristics including Ulcers and Performance in Growing Pigs

This report investigates the effects of disintegration method (grinding or rolling of the cereal part), feeding method (feeding twice a day or ad libitum) and straw as bedding (with or without) on empty stomach weight, volume, content, and the prevalence of gastric lesions in the pars oesophagea as well as on the performance in growing pigs. Four hundred growing pigs were included in the experiment. The grinding of the cereal was performed on a hammer-mill, mounted with a 3-mm screen or rolled on a roller mill. Performance was only slightly influenced by the disintegration method and the use of straw as bedding material. Ad libitum fed pigs, however, had a 5.5% higher (P<0.001) daily weight gain and a 0.6 percentage unit lower (P<0.01) lean meat percentage compared to pigs fed twice daily. Feed with rolled cereals increased (P<0.001) the empty stomach weight by 13%, but only in pigs not receiving straw bedding. Ad libitum feeding reduced (P<0.001) the empty stomach weight and volume by 15% and 37%, respectively. Feed with rolled cereals increased (P<0.001) the dry matter content of the stomach by 23%. The general level of gastric lesions in the pars oesophagea was low in this experiment, which most likely was due to the high content of barley in the feed mixture. The pigs receiving straw bedding, but also the pigs receiving rolled cereals but no straw bedding, had nearly no gastric lesions (average score=0.1), contrary to the pigs receiving ground feed but no straw bedding (average score=1.0). This interaction in gastric lesions between disintegration method and straw as bedding material indicates that feeding rolled cereals has similar preventive effects on gastric lesions as straw eaten.