Comparison of regression and fat-free diet methods for estimating ileal and total tract endogenous losses and digestibility of fat and fatty acids in growing pigs

Abstract

An experiment was conducted to 1) compare the regression and fat-free diet methods for estimating total or basal endogenous losses of fat (ELF) and fatty acids (ELFA) and true digestibility (TD) or standardized digestibility (SD) of fat and fatty acids in growing pigs and 2) compare these estimated values at the end of the ileum and over the entire intestinal tract. Ten barrows (initial body weight: 45.1 ± 2.8 kg) were surgically fitted with a T-cannula in the distal ileum, and allotted to 1 of 5 experimental diets in a 3-period Youden Square design. A fat-free diet was formulated using cornstarch, soy protein isolate and sucrose. Four oil-added diets were formulated by adding 4 levels of soybean oil (2, 4, 6 and 8%) to the fat-free basal diet at the expense of cornstarch. All diets contained 26% sugar beet pulp and 0.40% chromic oxide. Results indicated that here were no differences between true ileal digestibility (TID) of fat and true total tract digestibility (TTTD) of fat when pigs were fed soybean oil. The TID of C18:0 and total saturated fatty acids were greater than TTTD (P < 0.05). The total ELF at the end of the ileum was not different from that over the entire intestinal tract. In addition, total endogenous losses of C18:0 and total saturated fatty acids were greater for the entire intestinal tract than at the end of the ileum, whereas total endogenous losses of C18:2 and total unsaturated fatty acids were just the opposite. Similar results were observed for basal ELF and ELFA. As inclusion level of soybean oil increased, apparent digestibility of fat and fatty acids increased linearly (P < 0.05) except for apparent ileal digestibility of C18:0. However, SD of fat and fatty acids were not influenced by inclusion level of soybean oil. Estimation of ELF and ELFA observed by the regression and fat-free diet methods did not differ when measured at the end of the ileal or total tract. There were no differences between estimations of TD and SD of fat and fatty acids for soybean oil. Collectively, estimation of TD or SD of fat can be measured over the entire intestinal tract, whereas the ileal analysis method should be used to determine the ELF, ELFA and TD or SD of fatty acids. Correcting apparent digestibility for basal ELF and ELFA can accurately estimate SD values of fat and fatty acids.

Effects of dietary oil sources and fat extraction methods on apparent and standardized ileal digestibility of fat and fatty acids in growing pigs

“…Basal ELF and ELFA at the end of the ileum and over the entire intestinal tract were similar to our previous results [ 11 ]. Even when experimental conditions, such as fat-free diet composition, sample collection, and analytical procedures, were strictly controlled, small differences in basal ELF and ELFA can be observed between the two experiments.…”

“…Our previous study showed that correcting apparent ileal digestibility (AID) for basal endogenous losses of fat (ELF) and fatty acids (ELFA) obtained by the fat-free diet method can accurately estimate SID values [ 11 ]. Therefore, the objective of the current study was to determine the AID and SID of fat and fatty acids in different oil sources for growing pigs and to develop prediction equations for SID of fat based on fatty acid composition.…”

Intestinal organoids in farm animals

“…Intestinal organoids can also be used to test the effects of nutrients on epithelial homeostasis. For instance, the treatment of piglet organoids with dietary vitamin A reduced buddings and markers for differentiated cells while it increased stem cell markers [ 45 ]. In another study, treatment of pig organoids with glutamate increased epithelial proliferation [ 46 ].…”

Estimation of endogenous intestinal losses of acid hydrolyzed ether extract in growing and finishing pigs using the linear regression method

“…High true digestibilities are commonly observed after correction by EEE ( Gutierrez et al, 2016 ). The classical approach of using EEE is to assign digestible values to dietary sources ( Chen et al, 2019 ; Wang et al, 2020b ). However, knowing EEE becomes even more critical when researchers seek to model digestion and absorption of energy and nutrients in pigs ( Birkett and de Lange, 2001 ; Strathe et al, 2008 ).…”

“…Regression analysis has been used to quantify EEE and to calculate true digestibility of both complete diets and ingredients ( Jørgensen et al, 1993 ; Su et al, 2015 ). However, the regression method has not been tested under conditions more reflective of commercial practice; for example, most previous research has utilized purified or semi-purified diets combined with restricted feed intake ( Wang et al, 2020b ). To achieve precision in diet formulation, it is essential to understand if the relatively low concentration of EE found in cereal grains is of lower digestibility than EE provided by a fat-rich ingredient.…”