Digestibility of amino acids in pigs fed distillers dried grains with solubles derived from corn, sorghum, and triticale

An experiment was conducted to determine the standardized ileal digestibility (SID) of amino acids (AA) in distillers dried grains with solubles derived from corn (C-DDGS), sorghum (S-DDGS), and triticale (T-DDGS) fed to growing pigs. A total of 16 barrows [initial body weight (BW) = 23.1 ± 2.03 kg] surgically fitted with T-cannulas at the distal ileum were divided into four groups based on BW and assigned to a quadruplicated 4 × 2 incomplete Latin square design with four dietary treatments and two experimental periods. Three diets containing C-DDGS, S-DDGS, or T-DDGS, as well as a nitrogen-free diet, were fed in each experimental period consisting of 5 d of adaptation and 2 d of ileal digesta collection. Pigs fed S-DDGS had less (P < 0.05) SID of histidine, isoleucine, leucine, and methionine compared with those fed T-DDGS, which were less (P < 0.05) than the values observed for pigs fed C-DDGS. The SID of arginine, phenylalanine, threonine, and valine in C-DDGS were greater (P < 0.05) than in S-DDGS but were not different from those in T-DDGS. The SID of lysine in C-DDGS was greater (P < 0.05) than in S-DDGS and T-DDGS. In conclusion, AA in S-DDGS were less digestible than those in C-DDGS and T-DDGS.

Effect of microbial phytase supplementation on P digestibility in pigs: a meta-analysis

The objectives of this meta-analysis were to determine to which extent phosphorus (P) digestibility and digestible P concentration in pig diets were increased by phytase supplementation and to quantify factors that potentially influence effects of phytase supplementation. A data set with a total of 547 data lines was compiled from 88 experiments published in 74 peer-reviewed papers between 2007 and April 2019. An exponential model was determined as more suitable to describe the response of P digestibility to phytase supplementation than a polynomial model. Phytase supplementation increased P digestibility by 25.6 percentage points (standard error (SE) = 1.54) to a plateau at 64.9% (SE = 1.82). The digestible P concentration was increased by phytase supplementation in the order of 1.01 g/kg (SE = 0.102) to a plateau at 2.62 g/kg (SE = 0.122). Goodness-of-fit criteria were R² = 0.780 and root mean square error = 7.55% for P digestibility, and R² = 0.691 and root mean square error = 0.48 g/kg for digestible P concentration. Consideration of further factors such as mineral P supplementation (yes or no), ad libitum vs. restrictive feeding, mixed diets vs. single feed ingredients, sex and age of pigs did not increase the accuracy of prediction in this data set. Some of these traits exhibited responses, but they likely are artefacts generated through the imbalanced structure of the data set. Effects of dietary total P, phytate (InsP₆), InsP₆-P to total P ratio, and Ca on the effect of supplemented phytase were not quantifiable. The present meta-analysis showed that responses to phytase supplementation can be well predicted although variation in P digestibility and digestible P concentration in the data set was high. Overall, predicted effects of phytase on P digestibility well corresponded to predictions made 25 years ago.

Methodological aspects of determining phosphorus digestibility in swine: A review

The role of phosphorus (P) in swine nutrition has been taken on new significance in recent years. Methods to determine the available phosphorus (AP) content of swine feeds include relative bioavailability (RBV), apparent total tract digestibility (ATTD), standardized total tract digestibility (STTD), and true total tract digestibility (TTTD). The RBV of P is determined by measuring bone ash or bone P, whereas the ATTD of P is determined by calculating the difference between P intake and P excretion in feces. Recent research has shown that the use of ATTD of P underestimates the AP due to the existence of endogenous P in feces and digesta. The STTD can be calculated from ATTD by taking basal endogenous phosphorus losses (EPL) into consideration. The basal EPL in pigs can be measured by feeding a P-free diet. Values for STTD of P are believed to be additive in mixed diets but not for ATTD of P. The regression method is a common approach to determine total EPL and TTTD of P, which measures the linear relationship between fecal P excretion and the dietary intake of total P. In addition, in vitro methods such as the bionic enzymatic method are being increasingly utilized because they can be done quickly and simply. Several dietary factors such as P and Ca concentrations, phytate, Ca to P ratio and vitamin D may affect AP. This review summarizes the evolution of methods to measure AP and factors that can affect AP, which may provide information to formulate swine diet more accurately. Moreover, the knowledge about AP may help to reduce the P waste in swine production and thus decrease its impact on the environment.