| As more and more concerns have been focused on animal welfare, many countries has banned for surgical castration of boars. Nowadays, most farmers in our country still surgical castrated boars. During the process of castration, pigs would suffer huge pain, which seriously affected the welfare and behaviors of pigs. However, entire boars have boar taint. As a kind of resistant starch, raw potato starch could provide extra energy for microorganism in intestinal tract of pigs, thus, may change the behaviors of pigs. Raw potato starch could change the microorganism fermentation activity and levels of tryptophan, which might affect the synthesis of boar taint compounds. The aim of the study was to investigate the difference of behaviors, growth performance and boar taint compounds in different gender pigs, and the regulation of dietary raw potato starch. This thesis is constituted in the following three sections.In the first section, the differences of the behaviors in the period of lactation, nursing and finishing in different gender pigs were investigated. Fifty newborn piglets were selected in this study, which were nursed by 5 healthy lactating sows (each sow nurseing 2 female pigs,4 castrated and 4 entire boars). Since the beginning of nursing period, the female pigs, castrated and entire boars were raised separately. All pigs were fed the same diet. The behaviors of pigs in the period of lactation, nursing and finishing were observed and recorded, respectively. Results showed that the frequency of negative behavior in the castrated piglets (2.05%) was lower than the non-castrated piglets (entire male pigs and female pigs) (5.06%) in the period of lactation (P< 0.05). The positive, exploring and sucking behaviors in the castrated piglets had no difference with the non-castrated piglets (entire male pigs and female pigs) (P> 0.05). The frequency of rest behavior in castrated piglets (57.38%) was higher than the non-castrated piglets (entire male pigs and female pigs) (P< 0.05). On the 4th day of nursing period, the frequency of negative behavior in the castrated male pigs (12.50%) was lower than the entire male pigs (20.11%) (P< 0.05). On the 3th day of nursing period, the frequency of pisitive behavior in castrated male pigs (12.50%) was lower than the entire male pigs (15.63%) (P=0.09). On the 4th day of nursing period, the frequency in exploring behavior in castrated male pigs (35.17%) was lower than the entire male pigs (56.73%) (P= 0.09). On the 2th day of nursing period, the frequency of mounting behavior in the entire male pigs (17.50/90 min) was higher than the castrated male pigs (1.25/90 min) (P< 0.01). The frequency of negative behavior between entire male pigs (2.25/h and 3.25/h) and castrated male pigs had no significant difference (P> 0.05). However, mounting and positive behaviors in entire male pigs (5.63/h and 5.00/h, respectively) were higher than the castrated male pigs (1.38/h and 2.88/h, respectively) (P< 0.01). In conclusion, the activeness of entire male pigs was higher than the castrated male pigs. The mounting behavior in entire male pigs was higher than the castrated male pigs.In the second section, the differences of growth performance, boar taint compounds and growth development relative hormones in serum of different gender pigs were studied. During the period of experiment, the feed intake and body weight for each pig were recorded. At the age of 20,38,85,135 and 185 days, feces and blood samples were collected for skatole and indole analysis, as well as the androstenone, estradiol (E2), testosterone (T), triiodothyronine (T3) and growth hormone (GH) concentrations in the serum. Results showed that there was no significant difference on the average daily gain of different gender pigs in nursing and finishing period (P> 0.05). At the age of 185 day, the status of indole in serum and feces of entire male pigs (0.66 ng/mL and 9.52 μg/g, respectively) was higher than the castrated male pigs (0.43 ng/mL and 7.31μg/g, respectively) and female pigs (0.27 ng/mL and 5.54 μg/g, respectively) (P< 0.05). At the age of 20 day, the levels of skatole in feces of entire male pigs (72.17 μg/g) was higher than the castrated male pigs (48.28 μg/g) and female pigs (36.89 μg/g) (P> 0.05). At the age of 185 day, the growth hormone in serum of entire male pigs (2.12 ng/mL) had a tendency to be higher than the castrated male pigs (1.82 ng/mL) and female pigs (1.87 ng/mL) (P= 0.06). Serum testosterone levels of the entire male pigs at all period were significantly higher than the castrated male pigs and female pigs (P<0.05). In conclusion, the growth performance of pigs with different gender had no significent difference. Skatole and indole levels in serum and feces of the entire male pigs had a tendency to higher than the castrated male pigs. The entire male pigs had higher testosterone levels in serum than the castrated male pigs.In the third section, the effects of dietary raw potato starch on growth performance, boar taint compounds and behaviors of finishing boars in different gender pigs were investigated. At the end of the growing period (135 d) from the experimet one,20 entire and 20 castrated male pigs were choosen. They were assigned into 4 groups:entire boars+basic diet; entire boars+raw potato starch diet (5% raw potato starch); castrated boars+basic diet; castrated boars+raw potato starch diet (5% raw potato starch). The weight of initiate time (135 d) and the end of finishing period (185 d) was recorded. At the end of finishing period, feces and blood samples were collected for the analysis of skatole and indole levels, as well as the androstenone, estradiol, testosterone, triiodothyronine and growth hormone concentrations in serum. Four pigs from each group were selected. Negative, positive and mounting behaviors were observed and recorded twice a day. Results showed that dietary raw potato starch had no effect on daily gain of boars (P> 0.05). Raw potato starch could decrease the levels of skatole in serum and feces, but had no effect on androstenone in serum (P> 0.05). Person correlation results showed that skatole levels in serum had a significant positive correlation with skatole levels in fat of entire boars (r= 0.50, P< 0.05). Androstenone levels in serum also had a significant positive correlation with androstenone in fat of castrated boars (r= 0.62, P< 0.01). Negative, positive and mounting behaviors in entire male pigs with raw potato starch diet (1.25/ h,4.50/h and 5.50/h, respectively) were lower than the entire male pigs with basic diet (3.25/h,6.75/h and 8.50/h, respectively). Mounting and positive behaviors of the castrated boars were lower than the entire boars (P< 0.05). In conclusion, mounting and positive behaviors of the entire boars were higher than the castrated boars. Raw potato starch could decrease the occurrence of those behaviors, and could decrease skatole levels in serum and feces to some extent. |
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