A perennial schrub, stevia, and its extracts are used as a natural sweetener and have been shown to possess antimicrobial properties. Stevia contains high levels of sweetening glycosides including stevioside which is thought to possess antimicrobial and antifungal properties. Little is known about the nutritional value of the schrub in livestock. This study determined the potential use of the shrub as a prebiotic animal feed supplement in light of the recent ban on the use of antibiotics in animal feed and the role of its constituent stevioside in the effects of the shrub. Male Cobb broiler chicks were fed a basal broiler diet without antibiotic but with performance enhancing enzyme mix (positive control), a basal diet without antibiotic and enzymes (negative control), or diets in which 2% of the negative control diet was replaced with either dried ground stevia leaves or 130 ppm pure stevioside during 2 week starter and 2 week grower periods. Body weight gains, feed conversion, abdominal fat deposition, plasma hormone and metabolites and caecal short chain fatty acids (SCFA) were measured in the broilers at 2 and 4 weeks of age. There was no significant effect of the treatments on feed intake during the starter period but birds fed diet supplemented with stevia leaves and stevioside consumed more feed (p < 0.05) than those fed the positive control diet during the grower period. Weight gain by birds fed the positive control and stevioside diets was higher (p < 0.05) than those fed other diets only during the starter period. Feed/gain ratio of birds fed the positive control and stevioside diets was superior (p < 0.05) to others. There was no effect of the treatments on nutrient retention and water content of the excreta. Dietary stevia leave and stevioside decreased total concentration of SCFA and changed their profile in the ceca. There was no effect of the treatments on pancreas weight. Dietary stevia reduced blood levels of glucose, triglycerides and triiodothyronine (T(3)) but had no effect on non-esterified fatty acids. In contrast, stevioside only decreased T(3). Both the stevia leaves and stevioside diets significantly increased abdominal fat content. It is concluded that dietary enzyme growth promoters are beneficial to the broilers only during the starter stage and that inclusion of stevia leaves or stevioside has no beneficial effect on the performance of broilers.

The effects of inclusion of 8% oleic, palmitic, or a 50/50 mixture of oleic and palmitic acids as the major source of fat in the presence of .8, 1.2, or 1.6% calcium in broiler diets was investigated using broiler chicks from day-old to 3 weeks of age. Supplementation of broiler diets with oleic acid reduced feed intake (P less than .05) and improved feed efficiency (P less than .01) compared to other treatments. Chicks fed diets supplemented with oleic acid or a mixture of oleic and palmitic acid gained more weight (P less than .01) over a 3-week period. Significant interactions were observed between type of dietary fatty acid and calcium level on metabolizable energy of diets (P less than .01), magnesium retention (P less than .05), calcium and fat retention (P less than .01), and proportion of excreta fatty acid that was present as soap (P less than .01). Although all fatty acids tested formed soap in the small intestine, soaps of oleic acid were efficiently utilized as opposed to soaps of palmitic acid. There was a significant (P less than .05) reduction in bone ash and bone calcium content of chicks fed diets supplemented with palmitic acid. There was a significant interaction (P less than .05) between type of fatty acid and calcium level on bone magnesium content. Increasing the calcium content of diets aggravated the decrease in calcium retention and bone calcium content associated with addition of fat.

(Summers et al. 1976) as a measure of shell quality. Eggs collected during the last week of the trial were broken; the contents of the eggs were then freeze-dried, and ground prior to fat and fatty acid analysis.

Two experiments were carried out with young, Large White male turkey poults maintained in either floor pens or metabolism cages. In Experiment 1, poults were fed isoenergetic diets containing either no supplemental fat, or 5% of either tallow, corn oil, soybean oil, animal-vegetable blend fat, or canola oil. Poults generally ate less of the fat-supplemented diets and showed improved feed utilization, although weight gain was little affected. There was improved fat retention when vegetable oils were used (P < .01) and this was reflected in a slight improvement in diet energy level (P > .05). Poults fed tallow or animal-vegetable blend fat also excreted most fat. Diet had no effect (P > .05) on apparent retention of calcium or phosphorus, although retention of magnesium was less with more saturated fats. In Experiment 2, poults were fed diets containing palmitic acid, oleic acid, or a 50:50 (wt/wt) mixture of these fatty acids. There was a reduction (P < .05) in apparent retention of nitrogen, magnesium, calcium, and fat for poults fed palmitic acid, oleic acid, or the mixture. Mixing palmitic acid with oleic acid corrected some of these problems. However, reduced mineral retention was not reflected in any change in levels of bone ash, calcium, or phosphorus. Feeding palmitic acid did result in the most dramatic reduction of bone magnesium content (P < .05). It is concluded that turkey poults, like chicks, are less able to digest saturated fatty acids, and that such undigested fats can lead to reduced retention of some minerals through increased soap formation. However, there is no direct evidence that such soap formation causes a major change in bone calcium or phosphorus content or in gross bone development or poult well-being.

The effects of replacing 0, 33.3, 66.7 or 100% of dietary fish meal (9%) with housefly maggots (Musca domestica. Linn) was investigated using broilers from day old to 5 weeks of age.  Increasing the dietary level of maggots reduced feed intake and weight gain while increasing the feed: gain ratio (P>0.05), There was however no significant effect of dietary maggots on mortality rate (P>0.05). Replacement of dietary fish meal with maggots caused significant reduction in nitrogen retention (P<0.05) but an increase in fat retention (P>0.05). There was no significant effect of replacing dietary fish meal with maggots on the metabolizable energy value of the diets (P>0.05).  It is concluded that maggots could replace only 33% of dietary fish meal (9%) without compromising performance and nutrient retention in broiler chicks. The cost of harvesting and processing maggots is about 15% of equivalent weight of fish meal, making even partial replacement of fishmeal with maggots economical.