title: Evaluation of Dietary Supplementation with Antioxidants on Fertility Parameters in Stallions

authors: Blomfield, Jody Anne

subjects: antioxidants

abstract: The aim of the present study was to investigate whether dietary supplementation with antioxidants affects semen fertility parameters in New Zealand Standardbred stallions. Fourteen Standardbred stallions of varying fertility, from 3 studs located throughout New Zealand, were allocated to one of 3 treatments: minerals (Se, Cu, Zn, Mn) and vitamin E supplement, oil (canola) supplement and control (no supplement). The studs were provided with the supplements as aliquots to be added to each feed once per day. Stallions from one stud were fed a different basal diet from the other two studs. At least 3 semen samples were collected from each stallion and sent to Equibreed NZ Ltd, before, and after feeding the supplements for around 60 days.  Spermatozoa fertility parameters evaluated included total motility, progressive motility, total progressive motility, morphology (normal, loose heads, head defects, mid-piece defects, tail defects), acrosome status (FITC-PNA), membrane integrity (hypo-osmotic swelling test), and concentration. These parameters were assessed at various times including 6-8h and 24h after collection of semen, and immediately and 30min after thawing, frozen semen. Blood levels of Se, Cu and Zn were measured before and after supplementation. Per cycle pregnancy data was also obtained from questionnaire responses from studs A and B at the end of the trial. 
This study demonstrates that there was a statistically significant effect of feeding oil as a dietary supplement on sperm motility at 24h after collection (longevity) and also on the per cycle pregnancy rates when treatment groups were combined. Consequently, we were able to elucidate a difference in the actions of mineral and vitamin E supplementation when compared with oil supplementation on fertility parameters measured in this trial. Other beneficial effects of antioxidant supplementation on sperm parameters were suggested from the results of the fourteen stallions on two separate diets, but were not found to be statistically significant.

text: Evaluation of Dietary Supplementation with Antioxidants on Fertility Parameters in Stallions The aim of the present study was to investigate whether dietary supplementation with antioxidants affects semen fertility parameters in New Zealand Standardbred stallions. Fourteen Standardbred stallions of varying fertility, from 3 studs located throughout New Zealand, were allocated to one of 3 treatments: minerals (Se, Cu, Zn, Mn) and vitamin E supplement, oil (canola) supplement and control (no supplement). The studs were provided with the supplements as aliquots to be added to each feed once per day. Stallions from one stud were fed a different basal diet from the other two studs. At least 3 semen samples were collected from each stallion and sent to Equibreed NZ Ltd, before, and after feeding the supplements for around 60 days.  Spermatozoa fertility parameters evaluated included total motility, progressive motility, total progressive motility, morphology (normal, loose heads, head defects, mid-piece defects, tail defects), acrosome status (FITC-PNA), membrane integrity (hypo-osmotic swelling test), and concentration. These parameters were assessed at various times including 6-8h and 24h after collection of semen, and immediately and 30min after thawing, frozen semen. Blood levels of Se, Cu and Zn were measured before and after supplementation. Per cycle pregnancy data was also obtained from questionnaire responses from studs A and B at the end of the trial. 
This study demonstrates that there was a statistically significant effect of feeding oil as a dietary supplement on sperm motility at 24h after collection (longevity) and also on the per cycle pregnancy rates when treatment groups were combined. Consequently, we were able to elucidate a difference in the actions of mineral and vitamin E supplementation when compared with oil supplementation on fertility parameters measured in this trial. Other beneficial effects of antioxidant supplementation on sperm parameters were suggested from the results of the fourteen stallions on two separate diets, but were not found to be statistically significant.

year: 2010

title: Correlates of tree species sorting along a temperature gradient in New Zealand rain forests: seedling functional traits, growth and shade tolerance

authors: Lusk, Christopher H.

subjects: competitive hierarchies

abstract: 1.	It is widely believed that species sorting on environmental gradients reflects trade-offs between competitive ability and physiological tolerance of stresses such as frost and desiccation. One specific expression of this general idea is the hypothesis that tree species sorting on temperature gradients in temperate regions involves a trade-off between growth rate and frost resistance, because adaptations to frost reduce light interception and carbon gain potential.
2.	We measured seedling growth of 17 New Zealand rain forest angiosperm trees in a glasshouse, as well as biomass partitioning, gas exchange and hydraulic traits. We then related these variables to the mean July (winter) minimum temperatures most frequently experienced throughout the range of each species.
3.	Species associated with mild winters on average had wider vessels and more conductive stems and were leafier (i.e. developed more foliage area per unit sapwood area) than species from frostier sites. Species' positions on the temperature gradient were not significantly correlated with relative growth rates of seedlings; they were, however, negatively correlated with two measures of species light requirements in the field: the light compensation point for growth, and low-light mortality rates obtained from the literature.
4.	Synthesis. Although seedling growth rates of warm- and cool-temperate New Zealand angiosperm trees were similar on average, the former are more shade tolerant. Competitive hierarchies associated with tree species sorting on temperature gradients thus probably involve a shift in the relationship between shade tolerance and growth rate, rather than a simple trade-off of growth with cold tolerance. This shift is associated with variation in light interception potential per unit of seedling biomass, possibly reflecting a trade-off between stem conductivity and resistance to freeze-thaw embolism.

text: Correlates of tree species sorting along a temperature gradient in New Zealand rain forests: seedling functional traits, growth and shade tolerance 1.	It is widely believed that species sorting on environmental gradients reflects trade-offs between competitive ability and physiological tolerance of stresses such as frost and desiccation. One specific expression of this general idea is the hypothesis that tree species sorting on temperature gradients in temperate regions involves a trade-off between growth rate and frost resistance, because adaptations to frost reduce light interception and carbon gain potential.
2.	We measured seedling growth of 17 New Zealand rain forest angiosperm trees in a glasshouse, as well as biomass partitioning, gas exchange and hydraulic traits. We then related these variables to the mean July (winter) minimum temperatures most frequently experienced throughout the range of each species.
3.	Species associated with mild winters on average had wider vessels and more conductive stems and were leafier (i.e. developed more foliage area per unit sapwood area) than species from frostier sites. Species' positions on the temperature gradient were not significantly correlated with relative growth rates of seedlings; they were, however, negatively correlated with two measures of species light requirements in the field: the light compensation point for growth, and low-light mortality rates obtained from the literature.
4.	Synthesis. Although seedling growth rates of warm- and cool-temperate New Zealand angiosperm trees were similar on average, the former are more shade tolerant. Competitive hierarchies associated with tree species sorting on temperature gradients thus probably involve a shift in the relationship between shade tolerance and growth rate, rather than a simple trade-off of growth with cold tolerance. This shift is associated with variation in light interception potential per unit of seedling biomass, possibly reflecting a trade-off between stem conductivity and resistance to freeze-thaw embolism.

year: 2013

title: Turning a negative into a positive: Aquatic weed harvesting Lake Rotoehu

authors: Mallinson, Richard

abstract: The submerged aquatic weed hornwort (Ceratophyllum demersum) has become widespread through Lake Rotoehu since its establishment in the lake around 2000. This exotic pest plant is surface reaching in large parts of this shallow lake making it a perfect candidate for mechanical harvesting.
As part of the Te Arawa - Rotorua Lakes Programme the Lake Rotoehu Action Plan sets out nutrient reduction targets for nitrogen and phosphorus. Realising these targets is integral if lake water quality is to be restored to the trophic level index (TLI) target for Lake
Rotoehu. Restoration measures have included land use management efforts to arrest nutrient inputs, phosphorus locking through alum dosing, floating wetlands, and most recently the deployment of two aerators. To date the most successful in-lake nutrient reduction method has been mechanical harvest of hornwort.
Aquatic weed harvesting has resulted in reaching a significant portion of the annual nutrient target for the lake catchment. Attaining this level of nutrient removal has manifested in tangible water quality gains in the past few years. Most noticeable is the reduction in cyanobacterial (blue-green) algal blooms which had been prevalent in the lake in summer months. We discuss the practicalities and problems of submerged lake weed harvesting, disposal options, and impacts of this activity on the lake.

text: Turning a negative into a positive: Aquatic weed harvesting Lake Rotoehu The submerged aquatic weed hornwort (Ceratophyllum demersum) has become widespread through Lake Rotoehu since its establishment in the lake around 2000. This exotic pest plant is surface reaching in large parts of this shallow lake making it a perfect candidate for mechanical harvesting.
As part of the Te Arawa - Rotorua Lakes Programme the Lake Rotoehu Action Plan sets out nutrient reduction targets for nitrogen and phosphorus. Realising these targets is integral if lake water quality is to be restored to the trophic level index (TLI) target for Lake
Rotoehu. Restoration measures have included land use management efforts to arrest nutrient inputs, phosphorus locking through alum dosing, floating wetlands, and most recently the deployment of two aerators. To date the most successful in-lake nutrient reduction method has been mechanical harvest of hornwort.
Aquatic weed harvesting has resulted in reaching a significant portion of the annual nutrient target for the lake catchment. Attaining this level of nutrient removal has manifested in tangible water quality gains in the past few years. Most noticeable is the reduction in cyanobacterial (blue-green) algal blooms which had been prevalent in the lake in summer months. We discuss the practicalities and problems of submerged lake weed harvesting, disposal options, and impacts of this activity on the lake.

year: 2015