Peter Chrystal

In previous assays (Macelline et al., 2022), data on egg production rate (EP) and egg mass (EM) of Isa Brown layers from 27 to 33 weeks of age (peak production -PP) and from 42 to 48 weeks of age (Post PP) were used to predict amino acid (AA) requirements by fitting linear broken-line (LBL), and quadratic broken-line (QBL) models. Subsequently, the ideal ratios of Ile, Met + Cys, Thr, Trp, and Val ...

All grains, vegetable-based protein meals and their by-products used in poultry diets contain some levels of phytate phosphorous (PP). Depending on the ingredient type and source, a typical broiler chicken diet would contain between 2.2 to over 3.5 g/kg dietary PP. Research has shown that phytate anti-nutritional effects can reduce the digestibility of amino acids (AA) and minerals. Previously the ...

I. INTRODUCTIONIn Australia, the cost of tallow and vegetable oil has more than doubled over the past two years (www.finvis.com), prompting broiler nutritionists to re-evaluate dietary energy content for meat-type chickens. Globally, a wide range of lipids with diverse chemical composition, are routinely included in poultry feed including soapstocks or acid oil, crude vegetable oil, hydrogenated m ...

I. INTRODUCTIONMannan is a plant based-NSP derived from polymerisation of mannose sugars, it is categorised as galactomannan or glucomannan based on the presence of galactose and glucose side chains (Aspinall, 1973). Generally, galactomannan is the dominant form in legumes (Sundu et al., 2012). The ratio between mannose to galactose dictates the water solubility of galactomannan where galactose ha ...

I. INTRODUCTIONThe term ‘amino acid imbalances’ was probably originated by Elvehjem and Krehl (1955) and the topic was addressed by Harper and Rogers (1965). Their conclusion was that imbalances retard growth by altering the normal pathways of amino acid metabolism. Thus, while the relevance of amino acid imbalances to efficient chicken-meat production is recognised, a precise definiti ...

I. IntroductionGrains are the major energy sources in broiler diets. However, they also supply about 40% of the total dietary protein and contribute significantly to the provision of some indispensable amino acids (IAA; Szczurek et al., 2020). Despite the low protein content in maize, owing to its higher inclusion levels (50-70%) it may contribute approximately up to one third of the protein requi ...

I. IntroductionWheat and sorghum are the two major feed grains used in Australia for broiler diets; however, wheat is more common and is usually considered better quality than sorghum. The local chicken meat industry may have to increase by 60% to meet demand in 2050 so strategies are needed to promote sustainable chicken-meat production to meet this anticipated demand. Crude protein reductions in ...

1. IntroductionAs feed grade amino acids are commercialized at prices that are economically feasible for including in industry poultry diets, nutritionists are able to better supply diets containing amino acid profiles more closely representing ideal amino acid profiles (Baker, 1997). Refinement of dietary amino acid profiles allows for reductions in crude protein (CP), inclusion levels of protein ...