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    The kinetics of amino acid disappearance in the small intestine is related to the extent of amino acids absorbed in growing pigs
    (Cambridge University Press on behalf of The Nutrition Society, 2024-03-14) Montoya CA; van Bemmel M; Kreutz K; Hodgkinson SM; Stroebinger N; Moughan PJ
    This study evaluated the importance of a correction for amino acids (AA) released into the hindgut on a measure of AA absorption kinetics and tested whether AA absorption kinetics are related to the extent of AA absorption using the growing pig as a model for humans. Thirty-six nine-week-old pigs (22·3 kg) received a diet containing whey protein as the sole protein source for 8 d. Pigs received their last meal containing the indigestible marker titanium dioxide before being euthanised at 1, 2, 3, 4, 6 and 12 h post-feeding. The entire content of each gastrointestinal tract (GIT) region was collected to determine AA released into the hindgut, and the kinetics and extent of AA absorption (uncorrected and corrected for AA entering the hindgut). Amounts of AA released into the hindgut increased over time (e.g. 33 and 180 mg of Glu for 4 and 6 h post-feeding). The corrected apparent amount of each AA absorbed from the GIT lumen after 4 h post-feeding was generally lower (P ≤ 0·05) than the uncorrected counterpart. Differences in both the kinetics and extent of AA absorption were observed across AA. For example, the time to reach half of the apparent AA absorption (T50) was 1·5 and 3·4 h for Met and Arg, respectively, whereas their extent of apparent absorption was 93 and 73 %. Negative correlations between parameters related to kinetics and the extent of apparent absorption were observed (e.g. for T50 r = -0·81; P < 0·001). The kinetics of AA absorption is related to the extent of AA absorption.
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    Effects of ℓ-glucan and non-starch polysaccharides on ileal and faecal energy, nitrogen, ileal apparent and true amino acid digestibility in the growing pig : a thesis presented in partial fulfillment of the requirements for the degree of Master of Science at Massey University, Palmerston North, New Zealand
    (Massey University, 1999) Kim, Jae Cheol
    It is generally accepted that soluble non-starch polysaccharides (NSP) in cereals such as barley have a negative influence on the digestibility of energy, nitrogen, and amino acids in broiler chickens. However, the evidence in growing pigs for a similar effect of barley NSP on nutrient digestibility is less convincing. A major reason for this is that detailed investigations into the effect of barley NSP, predominantly β-glucan, have not been conducted. Therefore, the overall aim of this study was to elucidate the effect of NSP from a cohort of Australian barleys on the ileal and faecal digestibility of energy, nitrogen, and amino acids in growing pigs. This study was a collaborative project with the South Australian Research and Development Institute (SARDI). Eleven Australian barley varieties (including a control barley) were fed as the sole source of protein and energy to Landrace X Large White male pigs (35-55kg) fitted with a T-piece PVC cannula. Celite® was added as the indigestible marker. All diets were cold-press pelleted. Test diets were given to pigs based on a Latin Square design for five days prior to a two day collection period. An enzymically-hydrolysed casein (EHC) diet was fed to pigs for quantitative determination of endogenous amino acid flows at the terminal ileum. Ileal nitrogen, energy, apparent and true amino acid digestibilities were determined with reference to the marker. Faecal nitrogen and energy digestibilities were determined in six of the barley diets that were examined in New Zealand. An experiment with five barley varieties and one control barley was conducted in South Australia, and the same experimental protocol was followed at Massey University. The range in nutrient composition of Australian barley varieties was 7.6-14.2% CP, 12-21% NDF, 3-6% ADF, 0.5-1.5% Lignin, 2-4% total β-glucan, 0.21-0.34% soluble β-glucan, and 6-12% total amino acids on a dry matter basis. The six barleys that were examined in New Zealand were analysed for NSP and contained 11-17% total NSP, 7-11% insoluble NSP, and 2-7% soluble NSP. The contents of total NSP, soluble NSP, and soluble β-glucan were significantly correlated to CP content in barley (p<0.01, p<0.001, p<0.05, p<0.01, respectively). The ileal and faecal energy digestibilities of the barleys ranged from 53.6 to 71.0% and from 79.2 to 82.5%, respectively. Ileal and faecal nitrogen digestibilities ranged from 52.5 to 76.0% and from 64.3% to 75.6%, respectively. The mean apparent and true amino acid digestibilities were 69.7% and 84.1%, respectively. The mean endogenous Lysine flow determined under conditions of EHC/Ultrafiltration was 472μg/g dry matter intake. Correlation analysis between the chemical composition of the barleys and nutrient digestibility found significant positive relationships between ileal nitrogen digestibility and crude protein content (p<0.05), soluble μ-glucan (p<0.05), soluble NSP (p<0.05), and faecal nitrogen digestibility (p<0.05). Ileal energy digestibility was negatively correlated to insoluble NSP (p<0.05). No correlation was found between the chemical composition of barley and faecal nitrogen digestibility, while faecal energy digestibility was negatively correlated with NDF, ADF, and hemicellulose (p<0.05). The apparent ileal digestibility of essential amino acids was positively (p<0.05 - 0.01) correlated to ileal nitrogen digestibility, whereas no relationship (p>0.05) was found between true digestibility of essential amino acids and chemical composition of barley. Mathematical investigations found that the ileal (r2=0.66) and faecal energy digestibility (r2=0.73) could be predicted from the concentration of insoluble NSP and hemicellulose contents of barleys, respectively. Ileal nitrogen digestibility (r2=0.80) could be predicted from the concentration of CP and faecal nitrogen digestibility. Also, apparent ileal digestible lysine content (r2=0.99) could be predicted from faecal nitrogen digestibility along with the content of lysine in the barley. The anti-nutritive effects of NSP of Australian barleys were not observed in apparent ileal and faecal digestibilities of energy, nitrogen, and amino acids. However, a consistent tendency of the negative influence (p<0.05 - p>0.05) of NSP to true amino acid digestibility was demonstrated.
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    Effect of non-starch polysaccharides on blood lipid metabolites, organ weights, intestinal mucin production and endogenous losses in weaner pigs, and protein digestion in broiler chickens : a thesis presented in partial fulfilment of the requirements for the degree of Master in Applied Science (Animal Science) at Massey University, Palmerston North, New Zealand
    (Massey University, 2002) Padilla, Roy M
    This study was undertaken to examine the anti-nutritional influence of soluble non-starch polysaccharides (NSP) in two monogastric species. In experiment 1, the influence of NSP on blood lipid metabolites, organ weights, growth performance, mucin production, and endogenous nitrogen and amino acid flows were evaluated in pigs. In experiment 2, the influence of NSP on ileal nitrogen digestibility and flow were determined in broiler chickens. In experiment 1, different levels of purified maize arabinoxylan (AX) and barley β-glucan extract GlucagelTM (BG) were substituted for cellulose in enzymatically hydrolysed casein-based (EHC) diets. Five experimental diets consisting of different levels (4% and 7.5%) of AX and BG and EHC, wheat starch, sugars and coconut oil were formulated. These diets contained titanium oxide as an indigestible marker. Each experimental diet was fed to five 3-wk old LWxLR pigs for 21 days. The results showed that AX and BG did not significantly influence (P>0.05) the levels of blood metabolites measured after 21 days in fasted and fed states. Some blood metabolites showed significant changes over time. The levels of total cholesterol (TC), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) were significantly increased (P<0.05) after 21 days. On the 21st day, fasted and fed states were compared. Fasting significantly increased TC and some HDL levels, but LDL levels were not affected. The increase of blood metabolites over time was attributed to the interplay between increased synthesis in the liver and other tissues or decreased catabolism. Similar LDL values indicated differences of LDL metabolism between humans and pigs, which lack cholesteryl ester transfer protein (CETP) activity. Thus, very little HDL cholesteryl ester is transferred to LDL. The values obtained for empty organ weight were similar (P>0.05) between different diets although gut fill was significantly greater (P<0.01) with dietary inclusion of 7.5% BG, indicating the presence of gelling property of BG. Carcass weight and liveweight were similar (P>0.05) between diets. Daily feed intake (DFI) was also similar due to the restricted feeding scheme. However, weight gain (P<0.05) and feed conversion ratio (FCR) were improved (P<0.01) with dietary inclusion of 7.5% AX and BG, indicating high degradation rates of AX and BG molecules in pigs. This improvement was not due to the difference in gut fill. It could also be proposed that the threshold levels or length of time to initiate increased organ weights and affect growth performance was not achieved. Evaluation of crude mucin (CM) indicated a significant numerical increase in CM associated with increased level of AX, but not with BG. In the same trial apparent nitrogen digestibility (AND) ranged from 73.1% to 80.9% across diets. When corrected for endogenous losses, the range of true nitrogen digestibility (TND) across all diets became closer (88.36% to 90.7%). However, AND and TND were similar (P>0.05) in pigs fed different NSP. The endogenous nitrogen flow (ENF) showed numerical significant increase with increased level of AX, but not with BG. It is possible that the branched structure of AX molecules, which is difficult to breakdown, and its ability to hold water hampers digestion and absorption process and consequently leads to increased ENF and CM flow. BG may not be an anti-nutritional factor in pigs as implied by its high mechanical breakdown by microbes colonising the pig gut. Numerical increase in endogenous amino acid flows (EAAF) was observed with increased levels of AX but no definite trend with BG. In fact, EAAF in mixed NSP diets (4%BG and 3.5% cellulose) was even significantly higher than 7.5% BG. When pure NSP diets were compared, EAAF was highest in 7.5% AX (P<0.05), intermediate in BG, and lowest in control diet. Specifically, EAAF was highest for glutamic acid. Significant increased flow (P<0.01) for amino acid threonine, proline and serine with 7.5% AX are consistent with the high level of crude mucin found for this diet (i.e. those amino acids are abundant in mucin). In the second experiment, different levels (3% or 6%) of purified maize arabinoxylan (AX) and barley β-glucan extract GlucagelTM (BG) were substituted for wheat starch in cnzymatically hydrolysed casein-based (EHC) diets. Five experimental diets consisting of EHC, cellulose, wheat starch, dextrose and vegetable oil were formulated. These diets contained titanium oxide as an indigestible marker. Each experimental diet (control, 3% and 6% of BG or AX) was fed for 7 days to 27-day old birds in cages, with 4-5 birds/cage. Inclusion of AX and BG did not significantly influence feed intake (P>0.05). AND was numerically depressed at 90.37% and 90.4% for 6% AX and BG as compared to 91.1% for control diet. Ileal nitrogen content and endogenous nitrogen flow were numerically increased with increased levels of AX and BG, though statistically significant differences were not observed due to high variations among the replicates. Inclusion of 6% BG significantly depressed dry matter digestibility (P<0.05), suggesting preservation of hydration property of gelling BG. It is then concluded that the anti-nutritional effect of soluble NSP was evident in chicken as indicated by decreased dry matter digestibility (P<0.05) and the extent of increase in ileal flow of nitrogen in chicken. The cause of increased nitrogen flow with increased levels of NSP is not clear, but could be due to increased secretion of endogenous protein, decreased reabsorption, or combination of both. In pigs, dietary inclusion of arabinoxylan promotes anti-nutritional activity through its influence in nutrient digestion and absorption. This is shown by the increase of CM, ENF and EAAF (P<0.05) with increased level of dietary AX. This effect can be related to the ability of AX to hold water and their branched structure, which is difficult to degrade. Further, it would appear that gelling BG extract is likely well tolerated and its dietary inclusion seemed not a factor to negatively influence pig nutrition, at least with the levels used in this trial. The increase in ENF and EAAF associated with dietary inclusion of mixed NSP (4%BG and 3.5 % cellulose) is difficult to comprehend and is open for speculation. It is indicated that further research is needed to better understand the dynamics of cholesterol-lowering effect of NSP, and the effects of NSP on organ weights, ENF and EAAF. Such experiments should be conducted using relatively older animals and for a longer period of time.
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    Use of semi-anaemic piglets to measure iron bioavailability of meat and meat fractions: a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutritional Science at Massey University, Albany-Palmerston North, New Zealand
    (Massey University, 2003) Widjaja, Wisnudy
    Iron deficiency is a major nutritional problem. According to the World Health Organization (WHO), there are approximately 3.7 billion people in the world with iron deficiency (WHO, 2000). Red meat is known to enhance iron absorption due in part to the presence of a meat factor. Domestic pigs (Sus domesticus) have been utilised as models for humans in many medical and nutritional studies. The first experiment reported here used 20 4-week-old piglets to compare the bioavailability of iron in diets containing meat (ME), a water-soluble extract of meat (SA), a water-insoluble fraction of meat (SR), and a meat-free control diet (CO). Bioavailability of iron was assessed on the basis of changes in iron-related blood parameters over a 4-week feeding trial. Iron retention in haemoglobin, red blood cell counts (RBC), haemoglobin levels (HGB), haematocrit (HCT), and mean corpuscular volumes (MCV) for ME, SR, and SA was significantly higher (p < 0.05) than for CO indicating that all meat fractions enhanced the bioavailability of iron. For some blood parameters the iron status of group SA was significantly lower (p<0.05) than for groups ME or SR. It is concluded that the meat-factor is primarily present in the water-insoluble fraction of beef. In the second experiment nine four weeks old of age female pigs were allocated into three groups of diet treatments, i.e. E200, which contained 48 g/kg live weight0.75 of meat extrinsically labelled with Fe57; 1200 and 1300 , which contained 48 g/kg liveweight0.75 and 69 g/kg liveweight0.75 of meat intrinsically labelled with Fe57 The isotope labelled diets were fed only on day 0. Afterwards all pigs received the same weaner diet. The pigs were also injected by 58Fe via intra venous. E200, 1 200, and 1 300 were not significantly different (p > 0.05) in growth parameters (i.e. average daily gain and average daily feed intake) and in the blood parameters (i.e. white blood cells and RBC, HGB, HCT, MCV, the mean corpuscular hemoglobin and the total iron body in the blood circulation) and iron absorptions. The findings indicate that the different labeling method and different meat levels gave same results.
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    The energy and nitrogen metabolism and performance of pigs infected with Oesophagostomum dentatum : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science at Massey University, New Zealand
    (Massey University, 1981) Stewart, Margaret E.
    Two experiments, in which energy and protein metabolism and growth were measured, investigated the effects of infection with the nodular worm Oesophagostomum dentatum on growing pigs. In the first experiment, eight gilts were randomly assigned to one of two infection treatments (infected or uninfected). Each infection treatment was then randomly assigned to one of two planes of nutrition (high-plane or low-plane). Those being infected were dosed orally at 20 kg liveweight with 80,000 O.dentatum third stage larvae. Energy and nitrogen balances were repeated serially three times on each animal. Two open-circuit calorimeters were used, with the different treatments being distributed equally to each of these. O.dentatum eggs appeared in the faeces 19-26 days after administration of the larval dose, increased to a maximum concentration ranging between 4,475 and 18,275 eggs per gram (epg) faeces after 7 weeks and fell to concentrations ranging between 250 and 11,775 epg faeces at slaughter. All uninfected animals remained worm-free. Heat production (HP) and metabolizable energy intake (ME) were proportional to liveweight 0.66 (LW0.66). Therefore LW0.66 was used as the base to reduce variability in the data caused by variation in liveweight (LW). There were no significant differences between infected and uninfected pigs for intake, digestibility, metabolizability or retention of energy and nitrogen. Regression analyses of ER vs ME allowed ME required for maintenance (MEm ) and the efficiency of utilization of ME for growth (kg) to be calculated. The pooled value for MEm was 0.69 MJ.kg-0.66.day-1 or 0.49 MJ.kg-0.75.day-1. The pooled value for kg was 0.54 (calculated on the basis of MJ.kg-0.66.day-1) or 0.56 (caluclated on the basis of MJ.kg-0.75.day-1). There were no significant differences between treatments for either MEm or kg. In the second experiment, twenty-eight boars and gilts were assigned to one of two infection treatments (infected or uninfected). Those being infected were dosed at 20 kg liveweight with 80,000 O.dentatum third stage larvae. All pigs were individually fed once daily on the same feeding scale. They were weighed weekly and slaughtered at approximately 80 kg liveweight and the digestive tracts recovered. O.dentatum eggs appeared in the faeces at approximately 3 weeks post-infection, rose to a maximum concentration ranging between 2,825 and 36,250 (average 19,907) epg faeces at 6-13 weeks and then declined to between 50 and 25,825 (average 11,060) epg fresh faeces at slaughter. All uninfected animals remained egg-free. Average worm numbers recovered after slaughter were 4,255 per pig from infected animals. No worms were recovered from uninfected pigs. No differences were found between infected and uninfected pigs for growth or carcass characteristics.
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    Aspects of Trichinella spiralis in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Studies in Epidemiology at Massey University
    (Massey University, 2006) Richardson, Esther Katharine Barr
    In New Zealand, Trichinella spiralis appears absent from commercial pigs, and is not a significant cause of zoonotic disease. Surveillance testing at slaughter has not ever detected T. spiralis in a commercially raised pig in New Zealand, yet many importing countries still require individual testing of all pig carcases for export. This thesis comprises four studies designed to evaluate the risk of T. spiralis infection in commercial pigs in New Zealand. In the first study, the prevalence of T. spiralis was surveyed in selected populations of rats, cats, stoats and weasels from landfills, piggeries and Department of Conservation lands as they are considered potential reservoirs of T. spiralis for domestic pigs. No positive samples were detected in this survey. The second study investigated rodent activity and baiting efficacy on three commercial piggeries in the Manawatu region of New Zealand over 72 weeks. This study found that while baiting and on-farm sanitation can effectively control rodents, the efficacy of the control depends largely on staff commitment. The third study used a mail questionnaire sent to 123 piggeries, to survey current management practices on commercial piggeries that could pose a risk for Trichinella transmission. The survey had a 69% response rate and found that risky management practices occur infrequently in commercial piggeries. Lastly, a quantitative risk model was developed comparing individual carcass testing with alternative risk management strategies to assess the annual probability that a consumer in an importing country will eat a pork product of New Zealand origin containing at least one larva per gram of T. spiralis. Offals were found to always be safe. However, the unrestricted risk for fresh pork was over one in a million (1.87x10-5), which was above the safety threshold and therefore various risk management options were considered. The strategy of only exporting pigs reared in certified, confined commercial herds has now been accepted and is in place by the importing country. This means that individual carcass testing is no longer compulsory for every exported pig carcass.The overall conclusion from this research established a very low risk of T. spiralis infection and transmission in New Zealand commercial piggeries. These findings have directly led to successfully changing export legislation by removing compulsory carcass testing pre-export, which has advanced New Zealand’s ability to competitively export high quality pork and pork products.
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    An investigation of the aetiology and natural transmission of postweaning multisystemic wasting syndrome in pigs : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Studies in Epidemiology at Massey University, Palmerston North, New Zealand
    (Massey University, 2007) Jaros, Patricia
    Postweaning multisystemic wasting syndrome (PMWS) is a wasting disease primarily affecting weaned pigs. The disease causes significant production and financial losses through increased mortality rates and reduced daily weight gain. The aetiology is controversial although reports commonly suggest that PMWS is associated with the presence of porcine circovirus type 2 (PCV2) with disease expression modified by a range of infectious and non-infectious factors. While PCV2 infection in New Zealand is ubiquitous, PMWS has behaved as a propagating epidemic since its first incursion beginning in about 1999. The initial outbreak of PMWS in New Zealand was limited to a small cluster of farms near Auckland, which were epidemiologically linked to a possible entry mechanism. A transmission study was conducted in 2005 to critically evaluate alternative hypotheses which have been proposed for the causation and epidemiology of PMWS. The study set out to investigate the natural transmission of PMWS by direct contact between PMWS-affected and susceptible pigs, while managing the influence of proposed co-factors. Six different groups, comprised of pigs from PCV2-negative and positive herds were directly exposed to possible PMWS agents at 4 and 12-weeks-of-age and compared with two groups of unexposed pigs. All experimental groups were observed daily for 8 weeks or longer and evaluated clinically and pathologically. After exposure to PMWS-affected pigs, disease characterised by wasting, dyspnoea and high case fatality rates occurred in both PCV2-positive and PCV2-negative pigs of four-weeks-of-age, but not in pigs older than 12 weeks. Histopathological lesions found in experimental groups with clinical cases were consistent with those previously reported for PMWS. A range of infectious pathogens proposed to have a modifying influence on PCV2 and to contribute to disease causation were absent as determined by molecular and serological test methods. In addition, there was not sufficient molecular evidence to explain the genomic difference between PCV2 isolates from healthy and PMWS-affected pigs. Taking this, and supporting evidence from the other experimental groups into account, the findings of this study strongly support the conclusion that a transmissible agent other than PCV2 is involved in the causality of PMWS.