Two experiments were conducted to determine whether rice that has been genetically produced to express human lactoferrin (LF) or lysozyme (LZ) protects the intestinal tract similarly to subtherapeutic antibiotics (bacitracin + roxarsone; Antibiotics). Experiment 1 compared 10 corn-soy diets containing 20% of various proportions of LF, LZ or conventional rice (CONV). Chicks fed 5% LF + 10% LZ + 5% CONV had significantly better feed efficiency and thinner lamina propria in the duodenum than those fed 20% CONV. Experiment 2 compared five corn-soy diets containing experimental rice combinations totaling 15% rice. Chicks fed 10% LZ + 5% CONV or 5% LF + 10% LZ had significantly lower feed intake and significantly better feed efficiency than those fed 15% CONV. Chicks fed 10% LZ + 5% CONV, 5% LF + 10% LZ or Antibiotics had significantly greater villous height in the duodenum compared with chicks fed 15% CONV. The lamina propria of the ileum was thinner and contained fewer leukocytes in chicks fed 10% LZ + 5% CONV or Antibiotics compared with those fed 15% CONV. The results from these experiments demonstrate a potential of genetically produced LF and LZ rice to be used as a substitute for antibiotics in broiler diets.
USAInteractions between nutrition and immunity are diverse and have profound implications on animal growth and productivity. The innate immune system provides protection during the initial stages of infection and is responsible for mediating many of the alterations in nutrient metabolism. The macrophage is the key sensory and regulatory cell of the innate immune system. Their pro-inflammatory cytokines coordinate local immunity to pathogens, yet also act systemically to alter metabolic homeostasis and decrease food intake and growth rate. Altered energy, amino acid, lipid, and mineral metabolism have nutritionally important implications. For example, an innate immune response results in decreased uptake of amino acids by skeletal muscles and a corresponding increase in uptake by the liver and to a lesser extent by leukocytes. The net result is a decrease in amino acid requirements with no change in the efficiency of their use for growth. The shift in the priority of individual tissues for nutrients appears to be accomplished by changes in the types and amounts of their nutrient transporters and storage proteins. Adaptive immune responses result in considerably more subtle changes in nutrient metabolism than innate responses.
Roura, E., Humphrey, B., Tedo´, G. and Ipharraguerre, I. 2008. Unfolding the codes of short-term feed appetence in farm and companion animals. A comparative oronasal nutrient sensing biology review. Can. J. Anim. Sci. 88: 535Á558. The evolution of the chemical senses has resulted in a sensory apparatus for high taste and smell acuity in mammals and birds to ensure self-nourishment. Such peripheral chemosensory systems function as a code to unfold the nutritional value of feedstuffs. Food ingestion simultaneously evokes odor, taste and thermo-mechanical (somatosensing) sensations. Olfaction represents the capacity to identify feed volatiles that are predominantly derived from essential nutrients in plants.Comparative biology of olfaction shows that primates and chickens have a smaller olfactory epithelium and fewer olfactory receptor (OR) genes than non-primate mammals studied to date including farm and companion animals, such as the pig, the cow, the dog, the cat and the horse. A significant proportion of the total OR genes in mammals and birds have lost their functionality (pseudogenes) in a process that seems to reflect a decrease in the animal's reliance on the sense of smell, particularly in humans and cows. The taste system allows animals to recognize a diverse repertoire of nutrient (sugars, amino acids, salts, acids and fats) or toxic related chemical entities that provide valuable information about the quality of food. Taste senses non-volatile molecules in the oral cavity through taste receptors (TR). The TR are expressed in the sensory cells forming the taste buds of the tongue's papillae. Taste cells are linked to a network of solitary chemosensory cells diffused through many non-taste tissues involved in metabolic homeostasis. The number of functional taste receptor genes (TASR) in humans is equivalent to that in other mammals and superior to that in chickens. The TASR family 1 (TAS1R coding for umami and sweet TR) is conserved, in number and type, across the species evaluated, with the exception of the sweet receptor in chicken and feline species. The TASR family 2 (TAS2R coding for bitter TR) shows a strong adaptive capacity to dietary sources and digestive physiology across vertebrates. Pseudogenization (loss of gene functionality) in the TAS2R family seems to be a frequent strategy. The implications of oronasal nutrient sensing related to comparative animal feeding strategies and behaviors such as neophobia, feed refusal and hedonic preferences are discussed. Feed palatability and appetence might be one of the main driving forces in short-term feed consumption. Finally, practical applications relevant to animal production are outlined.Key words: Nutrient sensing, taste, olfaction, somatosensing, feed intake, farm, companion animals Roura, E., Humphrey, B., Tedo´, G. et Ipharraguerre, I. 2008. Le code de l'appe´tence a`court terme chez les animaux domestiques et de compagnie. Biologie comparative de la de´tection bucco-nasale des e´le´ments nutritifs. Can. J. Anim. Sci. 88: 535Á558. En e´voluant, ...
The diversity of taste perception across species reflects a dietary adaptation to different ecological niches. Laboratory rodents have been widely used as models for human nutritional studies including the understanding of peripheral chemosensing. Nevertheless the diet type as well as the anatomical and functional features of bigger mammals such as the pig may merit further consideration as models for humans. Recently, the porcine umami taste receptor pTas1r1/ pTas1r3 and porcine mGluR4 gene sequences have become available. The aim of this study was to compare the umami sensing biology with emphasis in T1R1 sequences, Venus flytrap (VFT) ligand binding domains and L-amino acid agonists of several mammalian species including human, pig and laboratory rodents. Compared to their corresponding human gene orthologues, receptor homologies where highest for the dog (T1r1 and T1r3) and the pig (mGluR4) and lowest for the mouse (T1r1, T1r3 and mGluR4). Th human T1R1 VFT domain contains 10 different amino acid residues critically involved in ligand binding. All 10 amino acid residues are conserved, both in terms of type and location, within the pig VFT domain. In turn, the arginine and histidine (both charged polar) residues at key positions 307 and 308 appear as threonine and tyrosine (both neutral polar) residues in mouse and rat sequences. Comparison of derived molecular models seems to offer a good explanation regarding the differences of in vivo preference data for L-amino acids in rats, pigs and humans. Overall, the umami sensing in pigs show higher similarity to that in humans than the umami sensing in laboratory rodents.
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