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    Capture and transport of white rhinoceroses (Ceratotherium simum) cause shifts in their fecal microbiota composition towards dysbiosis
    (Oxford University Press and the Society for Experimental Biology, 2023-11-24) Pohlin F; Frei C; Meyer LCR; Roch F-F; Quijada NM; Conrady B; Neubauer V; Hofmeyr M; Cooper D; Stalder G; Wetzels SU; Fuller A
    Translocations of Rhinocerotidae are commonly performed for conservation purposes but expose the animals to a variety of stressors (e.g. prolonged fasting, confinement, novel environment, etc.). Stress may change the composition of gut microbiota, which can impact animal health and welfare. White rhinoceroses in particular can develop anorexia, diarrhea and enterocolitis after translocation. The aim of this study was to investigate the associations of age, sex and translocation on the rhinoceros' fecal bacterial microbiota composition. fecal samples were collected from rhinoceroses at capture (n = 16) and after a >30-hour road transport (n = 7). DNA was isolated from these samples and submitted for 16S rRNA V3-V4 phylotyping. Alpha diversity indices of the rhinoceros' fecal microbiota composition of different age, sex and before and after transport were compared using non-parametric statistical tests and beta diversity indices using Permutational Multivariate Analysis Of Variance (PERMANOVA). Resulting P-values were alpha-corrected (Padj.). Alpha and beta diversity did not differ between rhinoceroses of different age and sex. However, there was a significant difference in beta diversity between fecal samples collected from adult animals at capture and after transport. The most abundant bacterial phyla in samples collected at capture were Firmicutes and Bacteroidetes (85.76%), represented by Lachnospiraceae, Ruminococcaceae and Prevotellaceae families. The phyla Proteobacteria (Padj. = 0.009) and Actinobacteria (Padj. = 0.012), amongst others, increased in relative abundance from capture to after transport encompassing potentially pathogenic bacterial families such as Enterobacteriaceae (Padj. = 0.018) and Pseudomonadaceae (Padj. = 0.022). Important commensals such as Spirochaetes (Padj. = 0.009), Fibrobacteres (Padj. = 0.018) and Lachnospiraceae (Padj. = 0.021) decreased in relative abundance. These results indicate that the stressors associated with capture and transport cause an imbalanced fecal microbiota composition in white rhinoceroses that may lead to potentially infectious intestinal disorders. This imbalance may result from recrudescence of normally innocuous pathogens, increased shedding of pathogens or increased vulnerability to new pathogens.
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    Exploring the association of personal factors with affective responses to plant-based meat alternatives with consideration of their perceived similarity to meat
    (Elsevier Ltd, 2025-12-01) Giezenaar C; Mehta A; Orr RE; Godfrey AJR; Foster M; Hort J
    Plant-based meat alternatives (PBMAs) have gained popularity as perceived sustainable replacements for meat, yet consumption remains limited. Understanding how personality traits shape PBMA consumption experience is therefore essential. This study surveyed 140 New Zealand consumers, assessing behavioural traits and attitudes related to willingness to reduce meat consumption/increase PBMA consumption. Participants completed tasting sessions evaluating commercially available PBMA products, based on flavour, texture, overall liking and emotions evoked, and sample perceived similarity to meat. Participants reported their demographic information, dietary habits, and frequency of meat and PBMA consumption. Results showed that higher social status derived from PBMA consumption were linked with higher liking ratings and citation proportion of ‘hungry’ for PBMAs. However, high negative attitude towards vegetarianism/veganism was linked to higher citation proportion for ‘unhappy’ for wholefood samples, while lower citation proportion for ‘unhappy’ for somewhat meat-like samples. High meat attachment was associated with lower perceived similarity to meat in both meat-like and somewhat meat-like samples. Additionally, the high meat consumption group reported lower texture and overall liking for meat-like samples. High variety seeking consumers (VARSEEK scores) were positively associated with flavour and overall liking for wholefood samples. Based on dietary groups, meat avoiders, generally driven by environmental and animal welfare concerns, reported more negative emotions such as ‘unhappy’ when tasting wholefood PBMAs compared to omnivores and flexitarians, despite their strong ethical and environmental motivations. The research highlights the impact of consumer behavioural traits and attitudes on their PBMA perception and acceptance, providing valuable insights for improving product development.
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    Effect of age on the standardized ileal amino acid digestibility of soybean meal and canola meal in broilers
    (Elsevier B.V. on behalf of KeAi Communications Co., Ltd., 2023-12-02) Barua M; Abdollahi MR; Zaefarian F; Wester TJ; Girish CK; Chrystal PV; Ravindran V
    Standardized ileal digestibility coefficients (SIDC) of nitrogen (N) and amino acids (AA) in two protein sources (soybean meal [SBM] and canola meal [CM]) were investigated at six broiler ages (d 7, 14, 21, 28, 35, and 42). Two assay diets were formulated to contain either SBM (413 g/kg) or CM (553 g/kg) as the sole dietary AA source. Titanium dioxide (5 g/kg) was added as an indigestible marker. A total of 696 male broilers at 1 d old were allotted to 12 replicate cages per age group. Each assay diet was offered to birds for 4 d prior to the ileal digesta collection on d 7 (14 birds/cage), 14 (12 birds/cage), 21 (10 birds/cage), 28 (8 birds/cage), 35 (8 birds/cage) and 42 (6 birds/cage), respectively. The apparent digestibility coefficients were standardized using age-specific basal endogenous AA flows. In the SBM group, though the SIDC of N tended to be influenced (quadratic; P = 0.075) by age, no linear or quadratic response of age effect was observed on the average SIDC of indispensable (IAA) and total AA (TAA). An age effect (quadratic; P < 0.05) was observed on the average SIDC of dispensable AA (DAA) in SBM with the highest value recorded at d 7, followed by a decrease from d 14 to 28, which increased beyond d 35. The SIDC of some individual AA (Arg, Thr, Trp, Cys, Pro) were affected (P < 0.05 or P < 0.001) in a quadratic manner by age. In the CM, the SIDC of N, average SIDC of IAA, DAA and TAA were influenced (quadratic; P < 0.05 or P < 0.001) by age. The SIDC of N and average SIDC of DAA and TAA were higher from d 7 to 14, declined at d 21, and then increased beyond d 28. The average SIDC of IAA was low between d 7 and 28 and increased thereafter. The SIDC of individual AA were affected (linear or quadratic; P < 0.05 or P < 0.001) by different magnitudes by age. The age influence on the SIDC AA was variable, depending on the protein source and AA. The results demonstrate that age-specific SIDC AA data might need consideration in broiler feed formulations.
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    Influence of feed form and age of broilers on energy utilisation of feed ingredients : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science (Poultry Nutrition) at Massey University, Palmerston North, Manawatu, New Zealand
    (Massey University, 2022) Khalil, Mahmoud Mohamed
    The accurate determination of the available energy of feed ingredients is crucial to optimise their inclusion in feed formulations and to improve the profitability and sustainability of poultry production. The metabolisable energy (ME) is commonly used for energy evaluation and formulating the diets for poultry. However, there are some limitations and several factors that influence the precision of the evaluation of the ME content of feed ingredients and diets. The current thesis investigated some of the unexplored research gaps on the ME of the commonly used feed ingredients in broiler diets. The first study presented in Chapter 3 was conducted to investigate the influence of feed form (FF; mash vs. pellet) on the apparent metabolisable energy (AME) and nitrogen-corrected AME (AMEn) of 7 single feed ingredients, four cereal grains (wheat, sorghum, barley, and maize) and three protein sources (soybean meal; SBM, canola meal; CM, and meat and bone meal; MBM). The influence of broiler age AMEn of cereal grains was investigated in Chapter 4 (direct method) and Chapter 5 (substitution method). The fourth experiment reported in Chapter 6 examined the effect of broiler age on the AMEn of protein sources. The experiments discussed in Chapter 7 were unique in that a novel methodology was developed for the quantification of the ileal endogenous energy losses (IEEL) in broiler chickens and for the correction of apparent ileal digestible energy (AIDE) to true (TIDE) ileal digestible energy of cereal grains (wheat, sorghum, barley and maize). The last trial of the thesis reported in Chapter 8 was conducted to refine-tune the IEEL methodology developed in Chapter 7 and to determine the influence of age and dietary cellulose contents on the IEEL estimates in broiler chickens. Data reported in Chapter 3 demonstrated that FF influenced the AMEn of feed ingredients. Pelleting increased the AMEn of all cereal grains by an average of 0.22 MJ/kg. However, for protein source ingredients, FF influence was ingredient-dependent. Pelleting increased the AMEn of CM by 0.57 MJ/kg, had no effect on that of SBM and decreased the AMEn of MBM by 0.56 MJ/kg. The experiment reported in Chapter 4 investigated the influence of broiler age on the AMEn of cereal grains using the direct method. The assay diets were formulated with an inclusion of 962 g/kg of each grain in the diet and pelleted. The data revealed that the age of broiler chickens has a significant impact on the AMEn of cereal grains. The first week of age recorded the highest AMEn for all cereal grains. Thereafter, the AMEn decreased either linearly (sorghum) or quadratically (wheat, barley and maize) with the advancing age of broilers. In the study reported in Chapter 5, the effect of broiler age on the AMEn of cereal grains, from the same batches used in Chapter 4, was examined using the substitution method. A maize-SBM basal diet was formulated and test diets were developed by replacing (w/w) 300 g/kg of the basal diet with each cereal grain. The results showed that the effect of broiler age on the AMEn varied depending on the grain type. Whilst the AMEn of barley and maize were unaffected by age, the AMEn of wheat and sorghum increased with the advancing age of broiler chickens. The determined AMEn values differed between direct and substitution methods, with the substitution method generating lower AMEn values. Data reported in Chapter 6 demonstrated that the AMEn content of SBM and CM was influenced by age of broilers. The first week showed the highest AMEn value for both SBM and CM, followed by reductions for both ingredients up to week 3 and increases thereafter. The studies reported in Chapter 7 present a novel approach to quantify the IEEL in broilers and correct the AIDE of cereal grains (wheat, sorghum, barley and maize) to TIDE enabling comparisons with AMEn. The IEEL was estimated to be 1.45 MJ/kg dry matter intake (DMI) in 21-d old broilers, following the feeding of a glucose-based purified diet and used to calculate the TIDE. The apparent ileal digestibility of dry matter, nitrogen and starch were positively and highly correlated with the TIDE than the AIDE or AMEn. The studies reported in Chapter 8 were conducted to refine the proposed methodology for the estimation of IEEL proposed in Chapter 7 and to investigate the influence of age of broilers and the dietary cellulose contents on IEEL estimates. It was found that the age of broilers had no impact on the IEEL estimates. The IEEL was affected by the cellulose content and the IEEL increased from 0.37 MJ/kg DMI for the diet without cellulose to 1.80 MJ/kg DMI for the diet with 75 g/kg inclusion of cellulose. The findings reported in the current thesis demonstrate that the application of AMEn values determined based on assays using mash diets might result in over- or under-estimation of the available energy content of ingredients in commercial pelleted broiler diets and highlights the need for the use of pelleted diets in energy evaluation assays. The findings also revealed that the effects of age and methodology are relevant in the determination of AMEn of feed ingredients and question the validity of using single AME or AMEn values for feed ingredients in broiler diet formulations across different ages. Another notable contribution was to develop a novel approach to quantify the IEEL in broiler chickens for the first time. The thesis research also provides preliminary data on the TIDE of common cereal grains and highlights the possibility of applying the TIDE as an alternative to the ME system in poultry feed formulation.
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    Investigations into the impact of feed form and age on the standardised ileal amino acid digestibility of feed ingredients for broiler chickens : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science (Poultry Nutrition) at Massey University, Palmerston North, Manawatu, New Zealand
    (Massey University, 2022) Barua, Mukti
    The importance of measurement of standardised ileal digestibility coefficients (SIDC) of amino acids (AA) in feed ingredients and their value in improving inter alia the precision of broiler feed formulations needs no elaboration. Databases on the SIDC AA of ingredients are accumulating during the past decade and various factors that influence the digestibility have been identified. Two aspects that remain unexplored hitherto in detail are the effects of feed form (FF) and broiler age. Previous AA digestibility assays were accomplished using mash diets because of the simplicity and the fact that research facilities often do not have access to pelleting equipment. As commercial broilers are fed pelleted diets, the data derived from mash diet may not be directly applicable. Another limitation is that, despite the potential age effects on AA digestibility, no study to date has investigated the influence of age on the SIDC AA in ingredients for the whole growth period of broilers. Lack of age-appropriate basal endogenous AA (EAA) flow data for the correction of apparent ileal digestibility coefficients (AIDC) is another constraint. Most of the existing EAA flow data were generated using older birds (21 to 42 d of age). The focus of this thesis research was to address these critical aspects. The first two experimental studies in Chapters 3 and 4 were conducted to determine the effect of FF (mash vs. pellet) on the SIDC AA in four grains (maize, wheat, sorghum and barley) and three protein sources (PS; soybean meal; SBM, meat and bone meal; MBM, and CM; canola meal) in broilers, respectively. Regardless of the grain type, FF had no significant (P > 0.05) influence on the SIDC of any AA, except for Cys and Pro, which were higher (P < 0.05) in mash diets. The effect of FF was more pronounced in the SIDC AA of PS. No influence of FF (P > 0.05) was observed for the SIDC of individual indispensable AA (IAA), except for His, the digestibility of which was lower (P < 0.05) in the pelleted diets. The SIDC of all individual dispensable AA (DAA), average digestibility of DAA and total AA (TAA) were reduced (P < 0.05) by pelleting. Cysteine was the most affected DAA, with a 15.4% reduction in SIDC in pelleted diets in comparison with mash. These results showed that the use of SIDC AA data generated from feeding mash diets may overestimate the AA digestibility in feed ingredients and affect the precision of broiler feed formulations. For this reason, pelleted assay diets were used in succeeding trials. The third study, reported in Chapter 5, was carried out to investigate basal EAA flow at different ages (7, 14, 21, 28, 35 and 42 d post-hatch) of broilers, following feeding of a nitrogen-free diet (NFD). The basal EAA flow of all individual and total AA were reduced quadratically (P < 0.05 to 0.001) as the birds grew older. The EAA flows were higher on d 7, then declined on d 14 and plateaued until d 35. A further decrease in the EAA flow was observed on d 42. These age-specific values were used in the correction of AIDC to SIDC in all ensuing thesis studies. The study presented in Chapter 6 was conducted to determine the influence of age on the SIDC AA in two grain sources (wheat and sorghum) in broilers. Six broiler ages (d 7, 14, 21, 28, 35, and 42 post-hatch) were investigated. Two assay diets were formulated to contain 938 g/kg of each grain as the only source of AA. Each assay diet, in pelleted form, was offered to birds for 4 d during the six periods namely d 3-7, 10-14, 17-21, 24-28, 31-35 and 38-42 prior to ileal digesta collection. In the case of wheat, no age influence (P > 0.05) was observed on the SIDC of average of IAA and DAA, though the average of TAA tended (linear, P = 0.09) to increase with advancing broiler age. In sorghum, the average SIDC of IAA, DAA and TAA were higher (linear or quadratic; P < 0.05 to 0.01) at d 7, declined at d 14 and then evened out. Among the IAA, the SIDC of Arg, His, Ile, Leu, Lys, Thr, Val, and the SIDC of all individual DAA (with the exception of Cys) reduced with advancing age (linear or quadratic, P < 0.05 to 0.001). The study reported in Chapter 7 was conducted to measure the SIDC of AA in maize and barley at six ages (d 7, 14, 21, 28, 35, and 42 post-hatch). Two assay diets were formulated to contain 938 g/kg of either maize or barley as the sole source of dietary AA. In maize, the average SIDC of IAA and TAA was affected in a quadratic manner (P < 0.05) with the values being higher at d 7 that dropped at d 14, increased and evened out between d 21 and 35, and decreased again at d 42. A linear influence (P < 0.05) was observed in the average SIDC of DAA. The SIDC of average IAA, DAA and TAA in barley was influenced (quadratic; P < 0.001) by age. The digestibility values increased from d 7 to 21 and then plateaued until d 42. The SIDC of all AA in barley increased (quadratic; P < 0.05 to 0.001) as the birds grew older. The final study, presented in Chapter 8, was conducted to determine the influence of broiler age on the SIDC AA in two PS (SBM and CM). Six age groups (d 7, 14, 21, 28, 35, and 42) were utilised. Two assay diets were formulated to contain either SBM (413 g/kg) or CM (553 g/kg) as the only source of dietary AA. In SBM, the average SIDC of IAA and TAA were not affected (linear or quadratic; P > 0.05) by age. The average SIDC of DAA in SBM was affected in a quadratic manner (P < 0.05) and the highest value was observed at d 7, that followed by a decline from d 14 to 28, and increased beyond d 35. The average SIDC of DAA and TAA in CM were higher (quadratic; P < 0.05 to 0.001) from d 7 to 14, reduced at d 21 and then increased beyond d 28. The average SIDC of IAA dropped between d 7 and 28, and followed by an increase thereafter. The novelties of this thesis research are that (i) no previous study has investigated the SIDC AA of feed ingredients from hatch to the end of broiler growth cycle, (ii) this is the first study reporting age-appropriate basal EAA flows and (iii) the use of pelleted assay diets that resembled the FF commonly used in the broiler industry. There were several original findings in this thesis. First, pelleting had substantial impact on the SIDC AA of feed ingredients and FF influence was more evident in case of ingredients with higher protein contents. Second, the EAA flow was higher in younger birds and reduced with advancing broiler age. Third, the age effect on the SIDC AA was variable depending on the ingredient and specific AA, and that the age effect on AA digestibility need to be considered in ingredient matrices for precise feed formulation.