The effect of dietary calcium inclusion on broiler gastrointestinal pH: quantification and method optimization

There is little consensus as to the most appropriate methodology for the measurement of gastrointestinal pH in chickens. An experiment was conducted to establish the optimum sampling method for the determination of broiler digesta pH in birds fed differing levels of dietary calcium. Ross 308 broilers (n = 60) were fed one of two experimental diets, one containing 0.8% monocalcium phosphate and 2% limestone and one containing 0.4% monocalcium phosphate and 1% limestone. Four factors were investigated to determine the most appropriate method of measuring broiler gastrointestinal digesta pH: removal from the tract, prolonged air exposure, altering the temperature of the assay, and controlling the water content of the digesta. The conditions were assessed at bird ages from 7 to 42 d post hatch. Dietary Ca content had no significant effect on in situ pH, but it contributed towards variance in ex situ pH of both gizzard and duodenum digesta

Protein Utilization and Requirements in Broiler Breeders

Advances in the genetics of poultry have created unintended consequences to the broiler breeder industry. Excessive weight has been shown to have many negative effects, including double hierarchies, multiple ovulations, and fatty liver. In an effort to curb excessive body weight gain, both the protein requirements and feeding strategies of broiler breeders are being revisited. A series of studies were conducted to determine the protein and amino acid requirements of broiler breeders during the production phase and to determine the interrelationship between protein turnover and egg formation. In the first trial, a 2x3x3 factorial study was conducted to determine the optimal energy x crude protein x pullet body weight combination to maximize egg production, fertility, and offspring weight. Results showed that 390 kcal and 22g CP were sufficient to optimize broiler breeder productivity. Protein utilization and nitrogen retention were most efficient at 22g CP intake. In the second trial, a 2x3 factorial study was conducted to determine how energy and crude protein impacts the partitioning of lysine during the egg formation process. Over 78% of dietary lysine was diverted towards egg formation, with the remaining being partitioned towards egg formation. However, the lysine in the egg was not solely of dietary origin. During early lay and at 45 wk, a majority of the lysine found in the egg yolk was from endogenous origins. Albumen was found to consist of primarily dietary lysine. No effect of energy and crude protein on portioning was determined. In the third trial, a 2x3 factorial study was conducted to determine the effects of energy and crude protein on protein turnover and the expression of proteolysis-related genes. Fractional degradation rates were found to increase during early lay and at 45 wk, but not at peak production. Expression of Fbox 32 protein, an indicator of ubiquination, was found to be elevated at the same periods degradation rates were found to be elevated. No changes to the proteasome and calpain 2 were observed that would explain changes to degradation rates. In the final two studies, the effects of low non-phytate phosphorus (NPP) on the diurnal patterns of bone turnover and the effects of carnitine supplementation on the fatty acid profiles of a hen and her eggs. Lowering NPP to 0.15% was found to diminish the amount of bone that is mobilized in an attempt to spare the skeletal integrity. Egg production is nonetheless reduced when NPP lowered to 0.15%. Finally, carnitine supplementation was found to increase the concentration of saturated and monounsaturated fatty acids in the egg and decrease the amount of polyunsaturated fatty acids in breeder abdominal fat

Torula yeast in the diet of Atlantic salmon Salmo salar and the impact on growth performance and gut microbiome

publishedVersio

First insight into the practical dietary application of Torula yeast single cell protein in gilthead sea bream

The growing global demand for sustainable and alternative protein sources in aquaculture has driven research into non-conventional feed ingredients, such as single cell proteins (SCP), as substitutes for fish meal (FM) and vegetable protein sources. The effects of dietary SCP from Torula yeast on growth, plasma biochemistry, and gut health were investigated for the first time in gilthead sea bream juveniles. Fish (initial weight: 24.7 ± 0.04 g) were fed for 76 days with four experimental diets containing increasing levels of SCP meal (0 % CTRL, 5 % SCP5, 7.5 % SCP7.5, and 10 % SCP10) as a substitute for FM. After the growth experiment (T1), fish were exposed to sub-optimal rearing conditions (temperature: 30 °C ± 0.4 °C; oxygen: 4.79 ± 0.51 mg L−1) for 8 days (T2). At T1, SCP7.5 exhibited growth and feed utilization more comparable to the CTRL group, whereas both SCP5 and SCP10 induced a drop. Additionally, SCP diets reduced AST, ALT, CK, and LDH plasma levels, particularly in the SCP10 group. Regarding the immune response, SCP7.5 enhanced local immunity, demonstrating the activation of both pro-inflammatory and anti-inflammatory pathways before and after exposure to high temperature-low oxygen conditions. The gut microbiome composition was influenced by dietary SCP, showing an increase in Bacillus sp. at both T1 and T2. According to PICRUSt2 analysis of gut microbiota functionality, the SCP5 and SCP10 diets promoted histidine metabolism. In conclusion, the findings indicated that 7.5 % SCP from Torula yeast can effectively replace FM. Additionally, Torula yeast exhibited functional properties like hepatic antioxidant function, and activating pro-inflammatory and anti-inflammatory pathways at the local level

106 Agriculture Residues as a Possible Sustainable Approach to Replacing Antibiotics in Animal Nutrition

Abstract The last several years has seen a substantial increase in the investment and development of alternative proteins to lower the environmental footprint of animal agriculture. In addition to insects, single cell proteins (SCP), i.e. algae, bacteria, yeast, have received renewed attention due to their ability to utilize unconventional carbon feedstocks. Traditionally, conventional sugar streams such as corn syrup or molasses have been used for cultivation of SCP. However, algal and bacterial meals are looked at as potential solutions for industrial carbon waste such as carbon dioxide and methane. Yeasts have the ability to use pentose sugars that are found in lignocellulosic materials, i.e. agricultural and forestry residues. Much of the discourse surrounding these alternative protein sources has been on the environmental impact of their production, but less so on the impact of their use. In particular, the impact of single cell proteins on nutrient utilization and gastrointestinal health warrants attention. Nutritional value remains varied among SCP products and dependent on microbial strain and down-stream processes. Maintaining high protein digestibility, and reducing fermentable protein, as well as maintaining high phosphorus digestibility remains a critical nutritional and environmental strategy. Recent findings have indicated that the microbial strain and the carbon feedstock on which it is grown on may have an interactive effect on gastrointestinal health. In particular, yeast products can be characterized as generally anti-inflammatory, but cultivation on lignocellulosic residues appears to enhance these properties. Bacterial meals are known to contain pro-inflammatory components such as lipopolysaccharides and peptidoglycans, however, in some instances, they may also produce bioactive molecules that result in a net positive impact. It remains critical to evaluate alternative proteins in the context of whole animal health and consider the environmental impact of their use as well as their production.</jats:p

New Insights on Defatted Algal Biomass as Single Cell Protein for Animal Feed

This information was presented at the 2012 Cornell Nutrition Conference for Feed Manufacturers, organized by the Department of Animal Science in the College of Agriculture and Life Sciences at Cornell University. Softcover copies of the entire conference proceedings may be purchased at http://www.ansci.cornell.edu/dm/proceedings_orders.html or by calling (607)255-4285