Abstract

Simple SummaryCanola co-products, which are included in swine diets as a source of amino acids, contain glucosinolates that limit the inclusion of these co-products in swine diets. Aliphatic and aromatic glucosinolates are two major canola co-product-derived glucosinolates. Aliphatic glucosinolates include progoitrin and gluconapin, whereas aromatic glucosinolates include 4-hydroxyglucobrassicin. Glucosinolates are non-toxic, but they are degraded into isothiocyanates, thiocyanate, and nitriles. Isothiocyanates produce goitrin, leading to reduced serum tetraiodothyronine concentration; thiocyanates lead to increased hypothyroidism; nitriles result in hepatic hypertrophy and hyperplasia. Canola-derived glucosinolates are degraded by heat during feed processing, in stomach acid (in the presence of iron), and by myrosinase in various sections of the gastrointestinal tract. Myrosinase is heat-labile and hence most of the myrosinase in canola co-products is inactivated during oil extraction. Notably, microorganisms are highly concentrated in the hindgut of pigs. Thus, the stomach and hindgut are the major sites of glucosinolate degradation in pigs. Most of the glucosinolates that escape degradation by acid in the stomach are degraded in the lower parts of the gastrointestinal tract. Practical swine diets contain iron; hence, degradation of glucosinolates in the stomach may not be limited by iron and may not be easily modified through changes in diet composition. Since the hindgut pH can be modified by diets fed to pigs, the composition of glucosinolate degradation products in the hindgut can be modified through diet modification. A reduction in hindgut pH of pigs due to dietary inclusion of highly fermentable dietary fiber can potentially favor the production of less toxic glucosinolate degradation products derived from canola co-products.Canola co-products are widely included in swine diets as sources of proteins. However, inclusion of canola co-products in diets for pigs is limited by toxicity of glucosinolate degradation products. Aliphatic and aromatic glucosinolates are two major classes of glucosinolates. Glucosinolate degradation products derived from aliphatic glucosinolates (progoitrin) include crambene, epithionitriles, and goitrin, whereas indole-3-acetonitrile, thiocyanate, and indole-3-carbinol are the major aromatic glucosinolates (glucobrassicin)-derived degradation products. At acidic pH (<5.7), progoitrin is degraded by myrosinases to crambene and epithionitriles in the presence of iron, regardless of the presence of epithiospecifier protein (ESP), whereas progoitrin is degraded by myrosinases to goitrin in the absence of ESP, regardless of the presence of iron at neutral pH (6.5). Indole-3-acetonitrile is the major degradation product derived from glucobrassicin in the absence of ESP, regardless of the presence of iron at acidic pH (<4.0), whereas thiocyanate and indole-3-carbinol are the major glucobrassicin-derived degradation products in the absence of ESP, regardless of the presence of iron at neutral pH (7.0). In conclusion, the composition of glucosinolate degradation products is affected by parent glucosinolate composition and hindgut pH. Thus, toxicity of canola co-product-derived glucosinolates can be potentially alleviated by modifying the hindgut pH of pigs.

Highlights

  • Canola co-products are the second most commonly used source of amino acids (AAs) in swine diets after soybean meal (SBM) [1]

  • The pH is the major factor that affects the composition of glucosinolate degradation products in the gastrointestinal tract (GIT) of pigs fed practical diets because of the following two reasons: First, the epithiospecifier protein (ESP) is susceptible to heat [19], and the ESP present in canola seed is inactivated during oil extraction

  • Progoitrin and glucobrassicin are the major aliphatic and aromatic glucosinolates, respectively, present in canola co-products fed to pigs

Read more

Summary

Introduction

Canola co-products are the second most commonly used source of amino acids (AAs) in swine diets after soybean meal (SBM) [1]. The composition of glucosinolate degradation products is dependent on various factors including the pH of the incubation medium and the presence of epithiospecifier protein (ESP; a non-catalytic cofactor of myrosinase) and ferrous ions in the incubation medium [4,18]. Of these factors, the pH (of the GIT) is the major factor that affects the composition of glucosinolate degradation products in the GIT of pigs fed practical diets because of the following two reasons: First, the ESP is susceptible to heat (is inactivated by heat at 60 ◦ C) [19], and the ESP present in canola seed is inactivated during oil extraction. A nutritional strategy that can contribute towards the optimization of utilization of canola co-products in diets for pigs is further discussed

Canola
Canola Co-Products
Glucosinolates
Effects of Purified Glucosinolates on Growth Performance of Pigs
Effects of Purified Glucosinolates on Organ Weights of Pigs
Glucosinolate Degradation Products
Factors Affecting Composition of Degradation Products of Glucosinolates
Degradation Products of Progoitrin at Acidic and Neutral pH
Degradation Products of Glucobrassicin at Acidic and Neutral pH
Various Factors Affecting Degradation of Glucosinolates
Reduction of Hindgut pH of Pigs
Findings
Conclusions
Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.