Fifty-four cross-bred ((Landrace×Yorkshire)×Duroc) pigs (13.47±0.03 kg average initial BW) were evaluated in a 42 d growth assay to determine the effects of the fermented soy product (FSP). The dietary treatments were: FSP 0 (corn-soybean basal diet), FSP 2.5 (FSP 0 amended with 2.5% FSP), and FSP 5 (FSP 0 amended with 5% FSP). The body weight at the end of the experiment increased linearly (p = 0.05) as the FSP levels in the diets increased. In addition, the ADG and G/F ratio also increased (linear effect, p = 0.06) as the levels of FSP increased. However, there was no effect of FSP on ADFI or DM digestibility (p>0.05). Furthermore, the N digestibility increased as the FSP levels increased (linear effect, p = 0.003), although the total protein concentration in the blood was not affected by FSP (p>0.05). Additionally, the albumin concentration was higher in pigs fed diets that contained 2.5% FSP than in pigs in the control group or the FSP 5 group (quadratic effect, p = 0.07). The creatinine concentrations were also evaluated at d 42 and found to be greater in pigs that received the FSP 2.5 diet (quadratic effect, p = 0.09). Moreover, the creatinine concentration increased linearly in response to FSP treatment (p = 0.09). Finally, although the BUN concentration on the final day of the experiment was greater in pigs that received the FSP 2.5 diet (quadratic effect, p = 0.10), there were no incremental differences in BUN concentrations among groups (p>0.05). Taken together, the results of this study indicate that feeding FSP to pigs during the late nursery phase improves growth performance and N digestibility.

A 6-week trial was conducted to investigate the effects of animal skin protein sources from swine and cattle on growth performance, body condition and blood characteristics in growing pigs. A total of 96 pigs (23.50 ± 0.61 kg) were randomly allotted into four dietary treatment groups as follows: (1) basal diet (BD); (2) basal diet with 1.5% hydrolysed render meal (HRM); (3) basal diet with 1.5% swine skin meal (SSM); (4) basal diet with 1.5% cattle hide meal (CHM). There were six replicate pens per treatment with four pigs per pen. The average daily gain (ADG) was improved in response to SSM treatment compared with other treatments (P < 0.05). Pigs fed with HRM, SSM and CHM diets showed increases in average daily feed intake (ADFI) and decreased gain-to-feed (G : F) ratios compared with pigs fed with BD (P < 0.05). There were no differences in dry matter (DM), nitrogen (N), and energy (E) digestibility among treatments. The backfat thickness and lean percentage of pigs was unaffected by the treatments. Similarly, there was no difference in blood characteristics among treatments. In conclusion, the supplementation of SSM in growing pig diets improved the growth rate and Feed Intake (FI), but its usage in swine diets is limited by the poor protein quality.