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Item Validation of prediction equations to estimate the nutritive value of broiler chicken diets based on their chemical composition(Elsevier BV, Netherlands, 2025-02-18) Thiruchchenthuran S; Zaefarian F; Abdollahi MR; Wester TJ; Morel PCHAn experiment was conducted to validate the accuracy of previously published prediction equations developed to estimate the coefficient of apparent ileal digestibility (CAID) and ileal digestible content (IDC) of nitrogen (N), crude fat, starch, calcium (Ca), phosphorus (P), energy, and dry matter (DM) in broilers using the chemical composition of diets. Twenty new diets were formulated to have a wide range of chemical characteristics relevant to commercial diets. The CAID of N, crude fat, starch, Ca, P, energy, and DM of the diets were determined in broiler growers fed ad libitum from 15 to 22 days post-hatch. The chemical composition and in vivo digestibility values were used to validate the prediction equations developed from a previous study. Comparison between the determined values and predicted values was used to assess the accuracy of prediction equations using the coefficient of determination (R2), root mean square error of prediction, concordance correlation coefficient (CCC), and mean bias (MB). The most accurate prediction was achieved in terms of R2 and CCC for CAID of energy and DM (R2 = 0.57 and 0.66, CCC = 0.45 and 0.47, respectively) as well as for IDC of N, starch, energy, and DM (R2 = 0.90, 1.00, 0.65, and 0.66, CCC = 0.48, 0.97, 0.51, and 0.47, respectively). The R2 and CCC values obtained for CAID of N, crude fat, starch, Ca, and P and IDC of Ca and P were not consistent with the expectation of predictive performance. The R2 for IDC of crude fat was high (0.94), however, CCC was moderate (0.43). The determined MB values showed that some equations underpredicted (CAID and IDC of N, crude fat, starch, energy, and DM) and some overpredicted (CAID of Ca and P and IDC of P) the observed values of in vivo study. In conclusion, the equations obtained for CAID of energy and DM as well as IDC of N, starch, energy, and DM could be considered the best fit according to R2 and CCC. Moreover, this study highlights the importance of validation with external data before applying each prediction equation to practical situations.Item Influence of different levels of black soldier fly larvae meal on growth performance and carcass quality of broiler chickens(Elsevier B.V., 2024-11-02) Baderuddin SH; David LS; Wester TJ; Morel PCHA study was conducted to examine the impact of two inclusion levels of Black soldier fly larvae meal (BSFLM) replacing soybean meal on growth performance, nutrient utilization, carcass characteristics and meat quality of broilers. Three experimental diets based on corn-soybean meal were developed to contain 0 (control), 6 (BSF 6) and 12% (BSF 12) BSFLMfor both starter and grower phases. Each experimental diet was randomly allotted to six replicate pens (eight birds per pen). The birds were offered starter pellets from 0 to 14 day post-hatch and grower pellets from 15 to 28 day post-hatch. The experimental diets were tested for pellet durability index (PDI). There was an interaction between diet and growth phase (P < 0.001) for pellet durability index where starter diets had always a higher PDI than the grower diets, but the difference was greater for control diet than BSF 6 and BSF 12 diets. Apparent metabolizable energy (AME) of diets and coefficients of apparent ileal digestibility (CAID) of nutrients were measured on day 28 using titanium dioxide marker ratios in the diet and excreta/ileal digesta. On day 28, the weights of live body, carcass, fat pad, breast and gizzard were recorded, and then breast meat quality (meat pH, drip loss and cooking loss) was examined. Inclusion of BSFLM of up to 12 % did not reduce live weight gain or feed intake. Live weight and carcass weight were heavier in broilers fed 12 % BSFLM than controls (P < 0.02), but were not different than those fed 6 %, while controls were not different than those fed 6 %. Breast weight (percentage live weight) was lower in birds offered 12 % BSFL than in others (P < 0.04). No differences were observed between diets for the percentage weight as carcass, fat, pad and gizzard. The AME and AMEc of diets were the highest in broilers fed 6 % BSFLM diet (P < 0.005), but there were no differences between controls and those fed 12 % BSFLM. The CAID of DM, ash and N in birds fed 6 % BSFLM were greater than (P < 0.03) birds fed 12 %, but were not different than controls, which were also not different than those fed 12 %. Broiler breast meat quality was unaffected by dietary treatments. In conclusion, BSFLM at 12 % can be used effectively as a SBM replacement in starter and grower diets, without affecting the growth performance, nutrient utilization, carcass characteristics and meat quality of broiler chickens.Item Prediction of cellular ATP generation from foods in the adult human : application to developing specialist weight-loss foods : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Nutritional Science at Massey University, Palmerston North, New Zealand(Massey University, 2010) Coles, Leah TheresaFor the accurate prediction of the potential ‘available energy’ of a food at the cellular level (i.e. ATP generation from food) it is necessary to be able to predict both the quantity and location of uptake (upper-tract or colon) for each energy-yielding nutrient. The objective was to develop a valid model (‘Combined Model’) for predicting the (potential) ATP available to the body from absorbed nutrients across the total digestive tract. The model was intended for the adult human under conditions where energy intake ≤ energy expenditure and all absorbed nutrients are catabolised. The development of the model involved two parts: (i) the experimental development of a dual in vivo – in vitro digestibility assay (‘dual digestibility assay’) to predict human upper-tract nutrient digestibility, as modelled by the rat upper digestive tract, and colonic digestibility, as predicted by fermenting rat ileal digesta in an in vitro digestion system containing human faecal bacteria; and (ii) the development of a series of mathematical equations to predict the net ATP yielded during the post-absorptive catabolism of each absorbed nutrient at the cellular level. A strong correlation (r=0.953, P=0.047) was found between total tract organic matter digestibility (OMD), as predicted with the newly developed dual in vivo – in vitro digestibility assay and with that determined in a metabolic study with humans for four mixed diets ranging considerably in nutrient content. There were no statistically significant (P>0.05) differences for mean OMD between the predicted and determined values for any of the diets. The Combined Model (dual in vivo – in vitro digestibility assay + stoichiometric predictive equations) was applied to three meal replacement formulations and was successfully able to differentiate between the diets in terms of both energy digestibility and predicted ATP yields. When the energy content of each diet was compared to that of a baseline food (dextrin), some metabolisable energy (ME) models gave considerably different ratios compared to that predicted by the Combined Model. By way of example, for Diet C a ratio of 0.96 (Atwater and FDA models) was found ii versus 0.75 (Combined Model). Thus, the model has practical application for predicting dietary available energy content, particularly in the research and development of specialised weight-loss foods, where it may be more accurate than some current ME models. Uniquely, the Combined Model is able to define a food in terms of ATP content (mol ATP / g food) using recent estimates of cellular P/O ratios and therefore, directly relates dietary energy intake to the quantity and form (ATP) of energy ultimately delivered at the cellular level.