There is increasing consumer demand for leaner and healthier
pork products. Improvements in genetics, new technologies, and
increased understanding of nutrition have become instrumental in
helping producers meet this demand. Continued research also has
led to the development of products that can be included in swine
diets as carcass modifiers. A dietary carcass modifier is broadly
defined as any component of the diet that alters the resulting
carcass composition of pigs. Generally, the mechanism of action of
carcass modifiers is aimed at increasing protein and muscle deposition
while reducing fat deposition. These products vary in the
mechanisms by which they modify carcass quality. In addition, not
all carcass modifiers are approved for use in pig diets, for public-health
reasons. Understanding the modes of action and differences
between these products is important for safe and effective use.Swine diets are composed mostly of plant-based ingredients.
Nutrients contained in these feedstuffs need to be broken down
by the pig into simpler forms that will be used to support maintenance,
growth, and reproduction. This poses a problem, because,
unlike ruminants, pigs do not have the ability to efficiently digest
plant components that have relatively high fiber content. Pigs lack
specific enzymes needed to break down fiber. Supplementing swine
diets with exogenous carbohydrate-degrading enzymes that break
down fiber has become increasingly popular to potentially improve
availability of nutrients from ingredients with high fiber content. Parasite control, in addition to control of viruses and bacteria,
must be part of a comprehensive herd-health program in every
swine production system. Gastrointestinal worm infections may
result in significant economic losses. Signs of infection are general
and not readily apparent, since worm infections rarely cause
elevated mortality levels. Some worms commonly found in pigs
are roundworms (Ascaris suum), nodular worms (Oesophagostomum
species), intestinal threadworms (Strongyloides ransomi), whipworms
(Trichuris suis), kidney worms (Stephanurus dentatus), and
lungworms (Metastrongylus species). Anthelmintics or “dewormers”
are chemical substances that can be added to pig diets to control
parasitic worms.
