Abstract
Clays are crystalline, hydrated aluminosilicate molecules composed of alkali and alkaline earth cations along with small amounts of various other elements. The best-known are montmorillonite, smectite, illite, kaolinite, biotite and clinoptilolite. The molecules in these clays are arranged in three-dimensional structures creating internal voids and channels capable of trapping a wide variety of molecules. As a result of this structure, clay minerals are regarded as a simple and effective tool for the prevention of the negative effects of many toxic compounds. Dietary supplementation with clays has been shown to improve weight gain and feed conversion in pigs. Where improvements in performance have been noted, one of the most likely explanations for the improvement is the fact clays increase nutrient digestibility. Clays reduce the speed of passage of feed along the digestive tract which allows more time for digestion. Feeding clays also causes morphological changes in the intestinal mucosa such as an increase in villus height and an increase in the villus height to crypt depth ratio. These changes increase the surface area of the gastrointestinal tract thus increasing nutrient digestibility. Several studies have indicated that feeding clay reduces the incidence, severity and duration of diarrhea in pigs. The mechanism for the reduction in diarrhea is likely due to increases in the numbers of Bifidobacteria and Lactobacillus and decreases in Clostridia and E. coli in the small intestine of pigs fed clays. In addition, the numbers of pigs born alive and weaned, birth weight and weaning weight have been shown to be higher for sows fed clays. Several studies have indicated that clays can help mitigate the effects of mycotoxins. The aim of the present review is to focus on the various clays which have been given attention in recent research and to discuss their potential to improve pig performance.
Highlights
Antibiotics are compounds used as growth promoters in animal feeds to decrease the animal’s susceptibility to infectious agents [1]
The aim of the present review is to focus on the various clays which have been given attention in recent research and to discuss their potential to improve pig performance
Xia et al [32] reported increases in the numbers of Bifidobacteria and Lactobacillus and decreases in Clostridium and E. coli in the small intestine of pigs fed 1.5 g/kg montmorillonite (Table 7)
Summary
Antibiotics are compounds used as growth promoters in animal feeds to decrease the animal’s susceptibility to infectious agents [1]. Clays with a 1:1 layer structure typically have a tetrahedral Si sheet covalently bound to an octahedral Al sheet Examples of this type of clay are kaolinite, dickite and nacrite, which belong to the kaolin group [10]. Many studies have documented a significant improvement in weight gain and feed conversion in pigs fed diets supplemented with clays [6, 7, 26,27,28,29,30,31]. Trckova et al [6] reported a 45 % increase in weight gain and a 16.9 % improvement in feed conversion ratio in weaned pigs fed diets supplemented with 1 % kaolin. Li and Kim [27] reported that growing pigs fed a diet supplemented with 0.5 % sericite had 6.6 % higher weight gain and a 5.1 % better feed conversion ratio compared with pigs fed an unsupplemented diet
Sign-in/Register to view highlights & summary 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 callDisclaimer: 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.
