Physiology of feeding in miniature pigs

Abstract

The anatomy and physiology of feeding in miniature swine were studied, using gross dissection, electromyography, cinematography, and cineradiography.Small particles are preferred for ingestion, and large items are usually broken down outside of the oral cavity. The particles are initially picked up with the lower lip and then retrieved by the tongue; the tongue very rarely leaves the oral cavity. Geniohyoid, mylohyoid and digastric are the most active muscles during food collection.Mastication is fairly rapid (3 cycleslsec) and involves a transverse component which may be either medially or laterally directed. The direction of motion is generally reversed with every chew. Electromyography indicates that the transverse rotation is caused by a force couple consisting of protrusors (masseter, medial and lateral pterygoids) on one side and retrusors (zygomaticomandibularis and temporalis) on the other. The direction of the rotation is not necessarily related to the side containing the bolus. Mandibular depression is electromyographically biphasic. Concurrent tongue and hyoid movements complicate the interpretation of activity patterns in the oral floor.Both masticated food and liquid are stored between the tongue and the soft palate and epiglottis before being swallowed. Swallowing involves very strong activity in all of the hyoid and tongue muscles and very low activity in the adductors. Liquid is taken in by suction rather than lapping.Comparisons with other mammals are presented.

A Preliminary Analysis of Correlations between Chewing Motor Patterns and Mandibular Morphology across Mammals

“…Many of the species examined here can be included in Weijs's (1994) transverse chewing group-in several cases, a ''herbivorous'' morphotype. A late peak activity of the BDM has evolved multiple times in mammals that exhibit significant transverse movements during chewing, including rabbits (Weijs and Dantuma 1981), pigs (Herring and Scapino 1973;Huang 1994), alpacas , horses (Williams et al 2003), anthropoid primates (Hylander and Johnson 1994;Hylander et al 2000), sifakas (a lemuriform strepsirrhine) , and koalas (Crompton et al 2010). Thus, it remains to be seen whether our results apply broadly to other mammalian groups, including rodent and carnivoran morphotypes, or more specifically to this transverse chewing group of mammals.…”

Internal Kinematics of the Tongue During Feeding in Pigs

“…These features suggested that expansion-contraction in the transverse (widening [AW, PDW and PVW] and thickening [RT and LT]) and sagittal (lengthening [RL and LL]) planes may better represent tongue internal kinematics during chewing and ingestion, respectively. Because sucking without lapping or licking occurs during water intake in pigs (Herring and Scapino, 1973), the tongue is subjected to more symmetric deformations with similar amplitudes in both transverse and sagittal planes during drinking (Fig. 5B).…”

Phenotypic Plasticity and Function of the Hard Palate in Growing Rabbits

“…Additionally, a number of similarities exist in the masticatory apparatus of rabbits and anthropoids, including a vertically deep face, position, and movements of the temporomandibular joint (Weijs and Dantuma, 1981;Crompton et al, 2006) as well as transverse jaw movements and jaw-muscle activity patterns (Weijs and Dantuma, 1981;Weijs et al, 1989;Hylander et al, 2000;Vinyard et al, 2008). Similar to many mammals, rabbit jaw-adductor activity patterns vary with dietary properties (Herring and Scapino, 1973;Luschei and Goodwin, 1974;Gorniak and Gans, 1980;Thexton et al, 1980;Weijs et al, 1987Weijs et al, , 1989Gans et al, 1990;Dessem and Druzinsky, 1992;Hylander et al, 1992Hylander et al, , 2000Hylander et al, , 2005, such that increased jaw-adductor recruitment results in elevated peak strains along the mandible and higher TMJ reaction forces (Weijs and de Jongh, 1977;Hylander, 1979aHylander, ,b,c, 1992Hylander et al, 1998;. Lastly, previous work on rabbit mandibular plasticity responses to postweaning alteration of dietary properties and masticatory stresses is consistent with similar experiments in a variety of other mammals (Beecher and Corruccini, 1981;Bouvier and Hylander, 1981, 1982, 1996aBeecher et al, 1983;Kiliardis et al, 1985;Bouvier, 1987Bouvier, , 1988Bouvier and Zimny, 1987;Block et al, 1988;Yamada and Kimmel, 1991;Ravosa et al, 2007bRavosa et al, , 2008a.…”