Nutrient digestibility, performance and bone characteristics of piglets fed diets with yeast phytase derived from Komagataella pastoris

Abstract

Apparent ileal (AID) and total tract (ATTD) digestibility assays were performed to evaluate the dietary inclusion of a yeast 6-phytase derived from Komagataella pastoris. For estimation of AID of phosphorus and calcium, eight castrated male pigs with an average body weight of 74 kg were used. The pigs underwent surgery for the implantation of a simple T-cannula in the distal ileum. Pigs were fed two dietary treatments: a positive control diet and a negative control diet with 500 FTU/kg of phytase. Diets were formulated to meet the nutrient requirements of finishing pigs, except for phosphorus in the diet with supplemental phytase. The AID of phosphorus for pigs fed the positive control diet was 41.98%, whereas for animals fed the T500 treatment it reached 54.25%. The AID of calcium for pigs fed the positive control and T500 diets were 60.58% and 58.85%, respectively. For estimation of the ATTD, twenty-four castrated male pigs with an average body weight of 30 kg were distributed across a completely randomized design with six replicates per treatment and one pig per experimental unit. The dietary treatments were composed of a low-phosphorus diet without phytase (negative control, NC) and NC diets + 250, 500, 750 and 1000 FTU/kg phytase. The effects of supplemental phytase on the digestibilities of dry matter, crude protein,calcium and phosphorus were evaluated. Data were analyzed using the GLM procedure of SAS version 9.4. Treatments were compared by the Dunnett's Test. Significance was declared at P≤0.05. The treatments did not influence (P>0.05) the parameters associated with the digestibilities of dry matter, crude protein, calcium and phosphorus. The dietary inclusion of 25 mg/kg (500 FTU/kg) of a yeast phytase derived from Komagataella pastoris improves the apparent ileal digestibility of phosphorus. The apparent total tract digestibilities of dry matter, crude protein, calcium and phosphorus were not influenced by the inclusion of phytase up to the level of 50 mg/kg (1000 FTU/kg).The other study aimed to evaluate the effects of feeding different levels of phytase derived from Komagataella pastoris on performance, bone characteristics and apparent digestibility of phosphorus in pigs during the growing and finishing phases. A total of ninety-six castrated male pigs were distributed into six treatments (Positive control: control diet without phytase;Negative control:low-phosphorus diet without phytase; Negative control diet with 250, 500, 750 and 1000 U/kg phytase) with eight replicates. The performance, phosphorus (P) digestibility, bone strength and concentrations of bone ash, calcium (Ca) and P were evaluated. Data were analyzed as a randomized block design using the GLM procedure of SAS version 9.4 (SAS Inst., Inc., Cary, NC). Treatments were compared by the Dunnett's Test. Regression analysis was performed to determine the optimal level of phytase in diets. Significance was declared at P ≤ 0.05. In phase 1, the feed conversion (FC) was influenced (P< 0.05) by phytase levels, and the worst FC ratio was reported in pigs fed the negative control diet. In phases 1 and 2, the treatments influenced (P< 0.05) the average final body weight, average daily gain and FC ratio, and the worst results were observed for pigs fed the negative control diet. Considering phases 1, 2 and 3, pigs fed the diet T1000 had higher AFW and ADG. Average carcass weight and yield were not influenced (P> 0.05) by treatments. The concentrations of bone Ca, P and ash werepositively and linearly influenced (P< 0.05) by treatments. Bone strength was quadratically influenced by treatments with phytase. The treatments did not influence (P> 0.05) P concentration in feces and P digestibility. Therefore, Apsa Phytafeed® yeast phytase derived from Komagataella pastoris improves the performance and bone mineralization of pigs during the growing and finishing phases. Supplementation of Apsa Phytafeed® is recommended at 37.5 mg/kg of feed.