| Presently, The current nutritional standards of the local breeds in China, almost all reference to foreign standards system, however, the formation history of our local pig breeds, size structure, feeding habits are very different of from foreign breeds. In addition, too much protein supply on feed to production sow, often result in increased fecal N discharge to the environment caused by pollution. Therefore, reasonable requirement of nutrients to domestic breeds come into a interesting research feild. Meishan pigs, originated in the Taihu Lake Basin, characterized with crude resistance high reproductive because of the natural environment and long-term low protein diet to it. With the promotion of intensive feeding, the diet Composition of Meishan pigs from the original green and crude food change to mainly concentrated feed, and the litter size also appears to decline. To test the effects of dietary protein on Meishan sows and their offspring, we fed Meishan sows diet with different protein levels during pregnancy and lactation (dietary crude protein content in control group sows during pregnancy is 12%, during lactation is 14%. dietary crude protein content in low-protein group sows is 50%of control). The body weight, organ weight and muscle weight of piglets, at different stages were detected. To further study the effects of diet protein levels to sow during gestation and lactation on antioxidant capacity in serum of piglets, we examined antioxidant enzyme activity of 70 embryonic pig placenta and the serum of piglets after the birth at different stages. These studies will further prove that Meishan sows reasonable level of protein nutrition to service Meishan pig feeding and management.1. Effect of maternal dietary protein level during gestation and lactation on parturition, piglet development and the economic benefitTwenty-four pure-breed primiparous Meishan sows were randomly divided into standard protein (SP) and low protein (LP) diet groups. Sows of SP group were fed diet containing 12%and 14%crude protein, while LP sows were fed contains 6%and 12% crude protein during pregnancy and lactation, respectively. Eight (4 from the SP,4 from the LP) sows were killed on day 70 of gestation. Placenta and feotuses were weighted; The other sows were raised following the standard feeding regimen with the starter until the parturition. newborn piglets were weighted and analyzed body size at parturition. Litter size was adjusted to 7 to 8 pigs per litter at 24 h post farrowing in the same group. Newborn piglets were allowed free access to their mothers and weaned at 35 days (d) of age. All piglets are weighted at weaning. After weaning, piglets were raised following the standard feeding regimen with the starter, grower and finisher diets recommended for the breed. The finishing at 184 days (d) of age were weighed and slaughed.The results showed that 1) feotuses weight of LP group decreased significantly (P< 0.05); the female feotuses of LP exhibited significantly lower body weight (P<0.05), but the male foetuses of LP group did not differ from that of SP group on body weight (P< 0.05).2) No difference was determined for placental weight between SP and LP groups.3) No difference were detected for the gestation, but the parturition time of LP group decreased by 22.63%(P> 0.05), interval of littering shortened by 28.96%(P>0.05).4) The mean number of the pigletsr from SP and LP was 8.55 and 10.25, respectively, and average survival piglets were 7.91 and 9.00, which exhibited that LP increase piglets number, but no significant difference in statistical analysis values. Survival rate of LP group decreased by 2.64%compard with SP group. Litter weight at birth of LP decreased by 14.4%with but no significant difference.5) No significant difference were analyzed for body height, body length, chest circumference between SP and LP.6) Piglets weight of LP group decreased by 1983.89g at weaning compared with SP group (P<0.01). But no significant difference in fattening weight were detected between SP and LP.These results indicate that maternal low-protein diet during pregnancy and lactation restricts fetal growth and development, and reduces fetal body weight on 70 d Embryo, piglet weight at newborn and weaning, and organ and muscle weight; LP didn’t affect the body weight of pigs at finishing stage, and indicates compensatory growth in LP group.2. Effect of maternal dietary protein level during pregnancy and lactation on organs and muscle weight of offspring To further analyze the effect of maternal dietary protein level on organs and muscle weight of offspring during pregnancy and lacatation, piglets at newborn (one male and female from 7-8 SP and LP, respectively) were killed, and liver, kidney, heart, spleen, longissimus muscle and psoas muscle were weighted. The remaining piglet were kept on respective (SP or LP) diets till weaning were killed, and liver, kidney, heart, spleen, longissimus muscle and psoas muscle were weighted. After weaning, piglets were raised following the standard feeding regimen with the starter, grower and finisher diets recommended for the breed. Finishing (184 day of age) stages, the 17 pigs (8/9 from the SP/LP) were killed the body, liver, kidney, heart spleen, longissimus muscle, psoas muscle and leaf fat were weighted for analysis. The result showed that 1) newborn piglet liver weight of LP group decreased by 5.95g compared with SP (P<0.01), kidney weight reduced by 1.128g (P< 0.05),and the adrenal glands weight was significantly lower than SP (P<0.01).But no significant difference was detected in the heart, lung and brain weight. No obvious difference was determined in Longissimus muscle weight, psoas muscle weight, and longissimus and psoas muscle ratio between SP and LP.2) Piglet at weaning, the weight of liver, kidney and spleen of LP decreased by 39.83g,13.03g, and 8.38g compared with SP respectively (P<0.01), but no difference was detected in lung weight. However, the heart weight of LP group showed a tendency of down-regulation. The ratio of brain and spleen to body weight was affected by the different dietary protein level (P<0.05), the other organ parameter was no difference between SP and LP groups. The Longissimus muscle weight of LP group decreased by 19.00g compared with SP(P<0.05), and the psoas muscle weight in decreased by 2.19g(P<0.05). And the ratio of Longissimus muscle in LP group was significantly lower than SP group(P<0.01), however, no difference in rate of the psoas muscle.3)For the fattening pig, no obvious difference was determined in liver, kidney, spleen, heart weight and organ parameter between SP and LP groups, but the offspring organ index of LP group showed a tendency of down-regulation. No significant difference was detected in Dorsi muscle, psoas muscle weight, organ index, and the suet index between SP and LP groups. But the suet weight of LP was significantly lower than SP group (P<0.05).The results indicat that the maternal low-protein diet during pregnancy and lactation has no significant effect on some organ development, in fattening phase, it mainly affects the accumulation of adipose tissue. The decrease of organ weight caused by the maternal low protein diet in pregnancy and lactation, may be involved in the oxidation stress of organism.3. Effect of mternal dietary protein level during sow pregnancy and lactation on antioxidant enzyme activity in placenta and piglet serum.Four sows(from SP and LP, respectively) were slaughtered on day 70 of gestation, placenta samples were taken for analysis. Plasma samples were taken from newborn piglets, weaning piglets and finishing pigs for analysis. SOD, MDA, T-AOC, GSH-Px and CAT activity were determined.The results showed 1) placental T-AOC and GSH-Px activity of LP group was significantly lower than SP (P< 0.01, P< 0.05). On difference was determined in placental SOD, MDA, CAT activity and total protein content between SP and LP group.2) SOD and GSH-Px activity in newborn piglet serum of LP group were significantly lower than SP (P < 0.05, P<0.01), no significant difference was detected in MDA, CAT, AOC activity. But male piglet GSH-Px activity of LP group was significantly lower than SP (P<0.01);female piglet GSH-Px activity of LP group was significantly lower than SP (P< 0.05), and no significant difference was detected in MDA, CAT, AOC and SOD activity between SP and LP groups.3) SOD activity Of weaning piglets in LP group was significantly lower than SP (P<0.05), and GSH-Px, CAT, AOC activity showed a trendency of down-regulation. No significant difference was determined in MDA activity between SP and LP group.4) No difference was detected in SOD, MDA, CAT, AOC, GSH-Px activity of fattening pigs serum between SP and LP group.These results indicate that maternal low-protein diet during gestation and lactation decreased placenta and piglet serum oxidative activity,exposed feotus or piglet to oxidative stress, and associated with low fetal body and birth weight. While after supply of the protein, oxidative stress restore and show significant compensation growth. |
PDF Full Text Request