| Arsanilic acid (p-Arsanilic acid, p-ASA) has been used as feed additives in animal husbandry for many years. The pollution of water and soil caused by arsanilic acid are growing more serious due to the large amount of p-ASA supplement and p-ASA excretion mostly in the form of prototype. That how to improve their utilization efficiency and reduce environmental pollution has become the focus of attention. Based on the characteristics of small size, easy absorption, small dosage, and less excretion of nanoparticle, therefore, p-ASA were processed into nanoparticle (p-Arsanilic acid nanoparticles, p-ASA?). The growth performance, growth-related hormones levels and digestive function in the rats were analysed to study the effect and mechanism of p-ASAP on growth promotion, and the arsenic contents in liver and feces of the rats were detected to study arsenic residues and utilization efficiency of p-ASAP.One hundred and twelve 35-day-old SD rats (56 male rats and 56 female rats) were randomly divided into seven groups,16 rats per group. The rats in Group A (control group) were fed with basal diet, the rats in Group B, C, D were fed with basal diet supplemented respectively with p-ASAP according to the dosage of 1/20,1/50 and 1/50 of their LD50, and the rats in Group E, F, G were fed with basal diet supplemented respectively with p-ASA according to the dosage of 1/20,1/50 and 1/50 of their LDso. The rats were fed for 7 days in advance, and the trial period was 36 days.The results were as follows:1. From day 8 on, the weight of the rats in each experimental group were higher than that in control group. On day 16, the weights of the rats in groups of D, F were significantly difference from control group (P<0.05).On days 24 and 36, except for Group E (P> 0.05), body weights of the rats in all experimental groups were significantly increased (P<0.01). From day 24, body weight of rats in each p-ASAP group were higher than that in the same dose of p-ASA group, indicating that p-ASAP and p-ASA have growth-promoting effect on rats, especially p-ASAP. The ratio of feed to weight in p-ASAP group was lower than that in p-ASA group (P> 0.05).It indicated that nanoparticles p-ASA feed conversion was slightly better than that of p-ASA.2. On day 36, compared with the control group, crude protein digestibility in each experimental group except Group E were higher, and in Group C and Group F were significantly higher (P<0.05). In all the experimental groups except Group G, fat digestibility were higher than that in control group, and in Group B and Group C were significantly higher (P<0.05). Compared with the same dose of p-ASA group, fat digestibility in Group B from p-ASAP groups was significantly higher than that in Group E (P<0.05). Crude fiber digestibility in all the experimental groups were higher than that in Group A,and in groups of B, C, D, F had significant difference (P<0.05). Compared with the same dose p-ASA group, crude fiber digestibility in groups of B, D from p-ASAP were significantly higher than that in groups of E and G (P<0.05). Crude ash digestibility was not significant among the groups (P> 0.05).3. On days 18 and 36, GH, T3, T4, NPY levels in all the experimental groups were higher than that in control group. On day 18, compared with the control group, GH and T3 levels in Group B and T4 level in Group F were significantly higher (P<0.05), NPY and T4 levels in Group B were significantly increased (P<0.01). On day 36, compared with the control group, GH level increased significantly (P<0.05) and T3, T4 levels increased significantly (P<0.01) in Group B; GH and T4 levels were significantly higher (P<0.05) and T3 level was significantly elevated (P<0.01) in Group C; NPY,T3 levels in Group E and NPY level in Group F were significantly higher (P<0.05), T3 level in Group F was significantly increased(P<0.01). Among the same dose of groups, GH and T4 levels in p-ASAP groups were significantly higher than that in the corresponding p-ASA groups (P <0.05), while NPY and T3 levels had no significant difference (P> 0.05).The experiment showed that p-ASAPand p-ASA had no significant effect(P> 0.05) on serum IGF-1 levels of rats(P> 0.05).4. On day 18, total liver arsenic residue in all the experimental groups were significantly higher than.that in group A (P<0.01). Total liver arsenic residue increased as the amount of supplemented p-ASAP and p-ASA increased. There were no significant difference (P> 0.05) between the same doses of groups in p-ASAP groups and p-ASA groups. On day 36, total liver arsenic residue in the experimental groups were significantly higher than that in group A, and total liver arsenic residue in groups of B, E, F were significantly elevated (P<0.01). Compared with the same dose of p-ASA groups, total liver arsenic residue in p-ASAP groups were lower than that in the corresponding p-AS A groups, but the difference was not significant (P> 0.05).On days 18 and 36, total arsenic contents of feces in all the experimental groups were significantly higher than that in control group (P<0.01), and elevated with supplemented doses increased. Compared with the same dose of p-ASA group, total arsenic contents of feces in p-ASAP groups were less, in which in Group C were significantly lower than that inGgroup F (P<0.05). Overall, the arsenic residue of feces in p-ASAP groups were lower than that in p-ASA groups.Conclusion:Dietary p-ASAP significantly improved growth performance in rats, increased crude protein, crude fat and crude fiber digestibility, reduced arsenic residue in liver and feces. |
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