title: The effects of food restriction on the perception of hunger, metabolic state and stress responsiveness in sheep

authors: Verbeek, Else

subjects: Feeding motivation

abstract: Sheep in temperate regions may be exposed to periods of limited food availability and a range of environmental conditions. Insufficient dietary intake may change live weight (LW) and body condition score (BCS) resulting in an increase in hunger and alterations in metabolic state, which may influence the welfare of sheep. In Chapter 2, a behavioural demand methodology to measure feeding motivation was refined and improved; five different walking distances (costs) were used and the number of rewards consumed, the total distance walked, Pmax (maximum price) and Omax (maximum expenditure) were used as measures of motivation. Sixteen non-pregnant ewes were subjected to two feeding levels (24 h fasted and ad libitum fed control); fasted ewes consumed more rewards and walked a greater total distance compared to control ewes. The methodology provided good measures of feeding motivation and was a potential indicator of hunger. However, the range of costs used was too narrow for accurate assessment of Pmax and Omax. In Chapter 3, the effects of body condition score (BCS) on feeding motivation and endocrine and metabolic responses in twin-bearing ewes were investigated to identify and quantify indicators of hunger and to assess the metabolic state of twin-bearing ewes with different BCS. Twenty-two ewes were divided into low BCS (LBC), medium BCS (MBC) and high BCS (HBC) treatments. Feeding motivation was assessed between day 91 and 105 of pregnancy and blood samples were collected once every 2 weeks between day 35 and 133 of pregnancy. The number of rewards consumed and Omax were significantly lower in the HBC ewes compared to LBC and MBC ewes, while the MBC ewes tended to show a lower motivation compared to the LBC ewes. LBC ewes were in a metabolically catabolic state and had low plasma concentrations of leptin, insulin and insulin-like growth factor-1. In Chapter 4, it was investigated whether a fast loss in BCS would increase hunger and alter the metabolic state more compared to a slow loss in BCS. Twenty-six twin-bearing ewes were assigned to Slow Loss (1 BCS loss in 13 weeks, SL), Fast loss (1 BCS loss in 10 weeks, FL) or Control (maintain BCS) treatments. Feeding motivation was assessed between day 42 and 67 of pregnancy and blood samples were collected once every 2 weeks between day 35 and 140 of pregnancy. SL and FL ewes had not lost much BCS at the start of the motivation period and no effects on feeding motivation were found. SL ewes were in a similar metabolic state as Control ewes. However, FL ewes were in a catabolic state in mid-pregnancy. In Chapter 5, it was investigated whether BCS affects the ability to maintain energy homeostasis and induce adaptive metabolic and stress responses to an environmental challenge. Eighteen shorn single-bearing ewes were divided into low, medium and high BCS treatments. Ewes were exposed to a 6 h acute cold challenge between days 85-87 of pregnancy. LBC ewes were able to maintain body temperature, but were slower to mobilise energy substrates and had a delayed and reduced cortisol response compared to MBC and HBC ewes. In conclusion, feeding motivation appeared to be an indicator of hunger in ewes; fasting and a loss in BCS markedly increased hunger. A loss in BCS induced a metabolically catabolic state. However, ewes were metabolically better able to adapt to a slow than a fast loss in BCS. Finally, low BCS ewes may have a reduced ability to respond to acute stressors.

text: The effects of food restriction on the perception of hunger, metabolic state and stress responsiveness in sheep Sheep in temperate regions may be exposed to periods of limited food availability and a range of environmental conditions. Insufficient dietary intake may change live weight (LW) and body condition score (BCS) resulting in an increase in hunger and alterations in metabolic state, which may influence the welfare of sheep. In Chapter 2, a behavioural demand methodology to measure feeding motivation was refined and improved; five different walking distances (costs) were used and the number of rewards consumed, the total distance walked, Pmax (maximum price) and Omax (maximum expenditure) were used as measures of motivation. Sixteen non-pregnant ewes were subjected to two feeding levels (24 h fasted and ad libitum fed control); fasted ewes consumed more rewards and walked a greater total distance compared to control ewes. The methodology provided good measures of feeding motivation and was a potential indicator of hunger. However, the range of costs used was too narrow for accurate assessment of Pmax and Omax. In Chapter 3, the effects of body condition score (BCS) on feeding motivation and endocrine and metabolic responses in twin-bearing ewes were investigated to identify and quantify indicators of hunger and to assess the metabolic state of twin-bearing ewes with different BCS. Twenty-two ewes were divided into low BCS (LBC), medium BCS (MBC) and high BCS (HBC) treatments. Feeding motivation was assessed between day 91 and 105 of pregnancy and blood samples were collected once every 2 weeks between day 35 and 133 of pregnancy. The number of rewards consumed and Omax were significantly lower in the HBC ewes compared to LBC and MBC ewes, while the MBC ewes tended to show a lower motivation compared to the LBC ewes. LBC ewes were in a metabolically catabolic state and had low plasma concentrations of leptin, insulin and insulin-like growth factor-1. In Chapter 4, it was investigated whether a fast loss in BCS would increase hunger and alter the metabolic state more compared to a slow loss in BCS. Twenty-six twin-bearing ewes were assigned to Slow Loss (1 BCS loss in 13 weeks, SL), Fast loss (1 BCS loss in 10 weeks, FL) or Control (maintain BCS) treatments. Feeding motivation was assessed between day 42 and 67 of pregnancy and blood samples were collected once every 2 weeks between day 35 and 140 of pregnancy. SL and FL ewes had not lost much BCS at the start of the motivation period and no effects on feeding motivation were found. SL ewes were in a similar metabolic state as Control ewes. However, FL ewes were in a catabolic state in mid-pregnancy. In Chapter 5, it was investigated whether BCS affects the ability to maintain energy homeostasis and induce adaptive metabolic and stress responses to an environmental challenge. Eighteen shorn single-bearing ewes were divided into low, medium and high BCS treatments. Ewes were exposed to a 6 h acute cold challenge between days 85-87 of pregnancy. LBC ewes were able to maintain body temperature, but were slower to mobilise energy substrates and had a delayed and reduced cortisol response compared to MBC and HBC ewes. In conclusion, feeding motivation appeared to be an indicator of hunger in ewes; fasting and a loss in BCS markedly increased hunger. A loss in BCS induced a metabolically catabolic state. However, ewes were metabolically better able to adapt to a slow than a fast loss in BCS. Finally, low BCS ewes may have a reduced ability to respond to acute stressors.

year: 2010

title: Properties of a thermostable β-glucosidase immobilized using tris(hydroxymethyl)phosphine as a highly effective coupling agent

authors: Oswald, Paul R.

subjects: tris(hydroxymethyl)phosphine

abstract: A very stable b-glucosidase (EC 3.2.1.21) was immobilized to polyacrylamide-magnetite beads, aminopropyl silica, and chitosan using tris(hydroxymethyl)phosphine (THP) or glutaraldehyde as the coupling reagent. The use of THP on chitosan resulted in greater than 90% yields with respect to free enzyme activity compared with only 60% observed when using the more conventional glutaraldehyde coupling reagent. THP-immobilized enzyme also lost activity more slowly than both glutaraldehyde-immobilized and the free enzyme when incubated at 90°C. Repetitive assays of THP and glutaraldehyde-immobilized enzyme also showed that THP was more able to retain active enzyme on the silica-based support. The pH optimum and Km app were unchanged with respect to free enzyme.

text: Properties of a thermostable β-glucosidase immobilized using tris(hydroxymethyl)phosphine as a highly effective coupling agent A very stable b-glucosidase (EC 3.2.1.21) was immobilized to polyacrylamide-magnetite beads, aminopropyl silica, and chitosan using tris(hydroxymethyl)phosphine (THP) or glutaraldehyde as the coupling reagent. The use of THP on chitosan resulted in greater than 90% yields with respect to free enzyme activity compared with only 60% observed when using the more conventional glutaraldehyde coupling reagent. THP-immobilized enzyme also lost activity more slowly than both glutaraldehyde-immobilized and the free enzyme when incubated at 90°C. Repetitive assays of THP and glutaraldehyde-immobilized enzyme also showed that THP was more able to retain active enzyme on the silica-based support. The pH optimum and Km app were unchanged with respect to free enzyme.

year: 1998

title: Te Aka Roa o Te Oranga, the far reaching vines of wellness: The development of a framework to evaluate alcohol and drug treatment for Māori

authors: Robertson, Paul

subjects: Maori

abstract: The impact of alcohol and other drug
problems for Māori is well documented.
Substance use has been implicated in a
range of physical and mental health
problems, and a variety of negative social
statistics such as high rates of imprisonment. To date there has been
little systematic documentation of treatment
practices, and limited operationalisation of
Māori health frameworks. The evaluation
of the outcomes of alcohol and other drug
treatments is an area in which there is a
paucity of documentation, in terms of
methods and frameworks for evaluation,
and actual data. Te Aka Roa O Te Oranga (TAROTO)
was developed from a range of projects
undertaken by the National Addiction
Centre. The TARATO evaluation framework
embraces a holistic perspective: developed
to examine the interaction between the
client, whānau, practitioner, and
service/organisation. The aim of the
framework is to clarify the complex
relationships and interactions between
stakeholders within the context of
treatment. It will also help to elucidate the
strengths and weaknesses of individual
services. Within this framework, a range of
indicators and outcomes of “successful
treatment” will be explored. The current project is the first phase of
a broader project that will make a
significant contribution to improvements in
Māori health via further developing
effective treatments of alcohol and other
drug related problems.

text: Te Aka Roa o Te Oranga, the far reaching vines of wellness: The development of a framework to evaluate alcohol and drug treatment for Māori The impact of alcohol and other drug
problems for Māori is well documented.
Substance use has been implicated in a
range of physical and mental health
problems, and a variety of negative social
statistics such as high rates of imprisonment. To date there has been
little systematic documentation of treatment
practices, and limited operationalisation of
Māori health frameworks. The evaluation
of the outcomes of alcohol and other drug
treatments is an area in which there is a
paucity of documentation, in terms of
methods and frameworks for evaluation,
and actual data. Te Aka Roa O Te Oranga (TAROTO)
was developed from a range of projects
undertaken by the National Addiction
Centre. The TARATO evaluation framework
embraces a holistic perspective: developed
to examine the interaction between the
client, whānau, practitioner, and
service/organisation. The aim of the
framework is to clarify the complex
relationships and interactions between
stakeholders within the context of
treatment. It will also help to elucidate the
strengths and weaknesses of individual
services. Within this framework, a range of
indicators and outcomes of “successful
treatment” will be explored. The current project is the first phase of
a broader project that will make a
significant contribution to improvements in
Māori health via further developing
effective treatments of alcohol and other
drug related problems.

year: 2003