2016 Seminar Series
Thursday 8th December 2016
The commercial poultry industry relies on a limited number of animal and vegetable protein ingredients. In general, animal protein sources have a higher nutritive value than vegetable sources but there are different constraints to the use of both sets of ingredients. Plant vegetable protein sources are poorer in nutritive value than animal protein, and their former may also contain anti-nutritive factors that limit the digestion of nutrients or directly affect animal health.
Soybean meal (SBM) is the premier plant protein used by the poultry industry around the world. The price of soybean meal do fluctuate but is generally high, particularly in importing countries. There are other vegetable protein sources of local importance around the world, for example, peanut, cottonseed, sesame seed and sunflower seed, some of these alternative sources are close to SBM and CM in nutritive value but they are either limited in supply or contain factors that inhibit productivity. Cottonseed meal (CSM) for example, is high in fibre and contains gossypol while sunflower seed meal (SFM) has a high level of fibre.
Tuesday 29th November 2016
Dietary feed ingredients represent 65-75% of total production cost while energy represents approximately 50% of the total diet cost. Nutrients, when assimilated yield energy that is vital to every function in the body. The total amount of feed energy is gross energy. By subtracting the energy portion eliminated in urine and faeces metabolizable energy (ME) can be calculated and used for feed formulation. Globally, most if not all poultry feeds are formulated using the ME system. Metabolism of feed in the body leads to heat production. Part of this is used to keep the body warm and the rest is heat increment or wasted energy. The ME system doesn’t consider heat increment. Formulating feed on a net energy system would take heat increment into account and thus may be more precise than the ME system. In this project, after establishing the equation for NE prediction an experiment was conducted to compare the feed energy evaluating systems on layer performance and economics.
Tuesday 7th November 2016.
Free- range egg production is getting popular in Australia as people are getting more concerned about awareness of hen welfare. This pressure encouraged Australian egg producers to house more free-range laying hens.
In free-range egg productions, hens are allowed to roam within a shed, and access a range. Subsequently, hens have the ability to express their natural behaviour. However, there are several challenges to be faced when housing free-range layers. For example, one of the most prevalent gastrointestinal parasite is Ascaridia galli. This parasite has been reported to decrease hen production and suspected to reduce egg quality. There is a lack of research on the impact of infection intensity on egg quality and a critical threshold that can be accepted. We investigated the impact of different infection levels with A.galli on hen performance (feed intake, body weight, egg weight, egg production) and egg quality parameters in free-range laying hens.
Tuesday 1st November 2016.
The ban and voluntary removal of in-feed antibiotics in the poultry industry throughout the world have led to the emergence of wet litter and enteric disorders. This results in poor performance of the birds thus reduced productivity and profit for the industry. To tackle such problems, alternative strategies have been sought which include the modulation of gut microflora, augmentation of immune response and control of pathogens through management, nutritional strategies and/or feed additives. These measures have shown to improve the health and digestive efficiency and thus improve growth performance of broiler chickens.
One of those strategies is incorporating structural components of feed, such as coarse fiber or ingredient in the diet. It is well documented that feeding birds with structural components of feed, such as coarse fiber or ingredient, modulate the gastrointestinal tract specially increasing the gizzard size. Large and well-developed gizzard can increase its grinding activity, leading to pancreatic enzyme secretion through increased release of cholecystokinin from pancreas, increased proteolysis by pepsin, trypsin and other endogenous proteases in the small intestine and improved GIT motility. It has been hypothesised that the feeding birds with fibre improve nutrient digestibility, growth performance, gut health, litter quality and bird welfare via enhanced GIT tract function, greater digesta transit time and improve faecal quality.
Our study aimed to investigate the effect of different sources of fibres along with different feed particle sizes on gizzard development, growth performance, nutrient digestibility, bird welfare and litter quality. The talk will present our findings which show the potential to use course ingredients and fibre to improve gut health, litter quality and growth performance of birds.
The Meat Standards Australia (MSA) beef grading model predicts the eating quality outcome of different cuts by cooking method from commercial inputs of on-farm, carcass traits and processing inputs. Based on a body of Australian research in the mid-2000’s it was demonstrated that Hormonal Growth Promotants (HGPs) have undoubtedly a negative impact on beef eating quality over and above an effect on maturity (ossification) and fat content, in the order of three to six palatability points (MQ4). Subsequently, an adjustment of approximately four to five MSA index points is applied to any carcase that is presented for grading whereby the animal was treated with a HGP.
Since the introduction of the HGP adjustment, some industry stakeholders argued that the research conducted to establish the magnitude of the HGP adjustment did not allow for the hypothesised variable effects of different HGPs used in Australia. This was because, in the majority of the studies conducted, animals received multiple implants and/or were finished with a combination trenbolone acetate and oestradiol HGP implant. This made individual implant contribution to eating quality effects, difficult to distinguish, and therefore, to protect the consumer, the MSA pathways committee decided on one collective HGP adjustment.
This seminar will present findings from a trial which compared the meat from steers finished in a feedlot with three HGP treatment groups; Control (no implant), oestradiol only implant (21.1 mg oestradiol-17ß) or combination oestradiol and trenbolone acetate implant (200mg trenbolone acetate and 20mg oestradiol). Samples from these animals were tasted by untrained consumers for tenderness, juiciness, flavour and overall liking as a measurement of eating quality. Further laboratory meat quality assessments were conducted as supporting data. Results indicate these HGP implants have different impacts on eating quality measurements.
Ancestors of domesticated fowl used today for meat and egg production, such as chicken, turkeys, ducks, amongst others, share an obvious commonality - their natural habitat. In the jungle, the presence of a number of predators and the necessity to eat and to survive in spite of them, have been pivotal for the development of some of the domestic fowl’s characteristics. According to zoology studies performed from as early as 1928, primitive eating habits and behaviours of the red jungle fowl would protect these birds from harsh conditions in the jungle. As observed by Baker and Baker (1928) in India, “During the heat of the day they [red jungle fowl birds] sleep in the forest in some tree or clump of bamboos but from dawn to about 9 am and again from 3 or 4 pm until dusk they may be seen wandering about in the crops.”
Increasing demands of a growing, wealthier and fast-paced worldwide population make dependency on seed-eating birds, hiding and sleeping on treetops throughout most of the day, highly unrealistic. As such, in spite of innately exhibiting an intermittent feeding behaviour, broiler chickens have been reared in commercial operations throughout the past decades on either continuous or near continuous illumination (23 hours of light and 1 hour or dark) or with daily, human-like schedules (16 to 18 hours of light and 6 to 8 hours of dark) and fed ad libitum, and continue being so in most operations, in the certainty that this practice maximizes feed intake and growth rate (Lewis & Gous, 2007).
Roles of certain parts of the digestive tract of chickens seem to have been lost with the evolution of time and commercial practices. Gizzards no longer serve their grinding purposes, having become more like transit organs and crops have lost their function with the abandonment of discontinuous feeding systems. Certainly, the importance of the crop in digestion will presumably be much affected by the proportion of feed that enters the crop and the amount of time it spends there.
What if regaining crop and gizzard functionality, by increasing particle size, reintroducing scheduled feeding and increasing dark periods, would enhance endogenous and exogenous enzyme activity, thus leading to better nutrient digestibility, less undigested feed in the caecum, less gut inflammation and therefore better performance and better animal health?
Arabinoxylan is a non-starch polysaccharide, and it is a common substrate in most xylans forming plant cell wall structure of cereal grains. The presence of arabinoxylans has been proven to implement various adverse effect in monogastric animals, for example, occurrence of insufficient digestion and unwanted fermentation. The poultry diets are pressed from cereal grains, including viscous grains, such as wheat, barley, rye and oats, which have a considerable amount of soluble non-starch polysaccharides. Therefore, xylanase products were widely used in the poultry production to i) partially depolymerise non-starch polysaccharides in the feed ingredient and ii) increase the nutritive value of grains by breakdown cell walls to release encapsulated nutrients. In spite of that, the excess amount of non-starch polysaccharides can destabilise normal gut microflora, thereby making intestinal environment vulnerable to the occurrence of necrotic enteritis.
Recent studies showed that arabinoxylan-oligosaccharides (AXOS), a depolymerisation of arabinoxylans by xylanase, could positively cultivate composition and activity of bacterial colonies in the gastrointestinal tract by selectively fermenting normal gut commensals. This particular finding may be an approach to strengthen the resilience of broilers against gastrointestinal pathogens and improve the nutrient utilisation from the feed ingredient.
The seminar will present findings from two experiments conducted at the UNE regarding the effect of xylanase inclusion as well as the supplementation of arabinoxylan and AXOS to broiler growth performance under necrotic enteritis challenge stress. Also, the response of gut viscosity and intestinal pH by arabinoxylans and AXOS supplementation will be discussed.
Turkey haemorrhagic enteritis (HE) is caused by a group II avian adenovirus known as Haemorrhagic Enteritis virus (HEV). HE is an acute disease of young growing turkeys with a sudden onset of depression, bloody droppings and a potentially high death rate. HE virus is present in Australia and outbreaks in 7-8 week old broilers with mortality of 0.5-1% over a week. It is also considered to be a historical cause of loss of illness, production and mortality in commercial turkey operations typically causing splenomegaly, mortality and increased E. coli infections at around 8-12 weeks of age.
Similar virus causes marble spleen disease in pheasants and avian adenovirus splenomegaly (AAS) in chickens. The disease is controlled by live virus vaccination worldwide but not Australia although a relatively avirulent strain HEV086 was isolated 30 years ago. The vaccine is produced from lymphoblastoid cell line MDTC-RP19 that is not available in Australia. It’s not possible to import this cell line to produce vaccine due to quarantine restriction. In addition, Australia does not have SPF turkey to produce the HEV vaccine but has SPF chicken and SPF eggs. The recent studies at University of New England examined to grow the HEV virus in SPF chickens and eggs. The qPCR results showed that best chicken produce 10,000-130,00 doses of vaccine from liver and spleen combined. Moreover, virus grows in SPF eggs with low recovery dose.
Most non-ruminant animal nutritionists would be familiar with the use of commercial soybean meal (SBM) in diets for poultry and pigs. Raw soybean meal (RSBM) is less commonly used due to high levels of anti-nutritive factors (ANF), particularly trypsin inhibitors (TI). The development of new highly potent microbial enzyme products offers an opportunity for the use of RSBM in areas where facilities for processing SBM are lacking.
In recent studies completed at the University of New England, PhD Student, Mammo Erdaw, examined the potential benefits of feeding RSBM in diets when supplemented with high-potency microbial enzymes.
The results showed that moderate dry- and wet-heating do not substantially reduce the levels of TI in RSBM, and diets were not substantially improved when cold- or steam-pelleted. Replacing SBM with RSBM at up to 25 % reduced body growth, due mainly to a reduction in feed intake and nutrient digestibility. The ingredient also increased endogenous losses of protein and amino acids, but did not affect the health of birds or the rearing environment. The negative effects of RSBM were reduced through dietary supplementation with microbial phytase and protease. A preliminary cost-benefit analysis also showed that RSBM could save feeding costs when it replaced SBM. Further studies are underway to directly assess the behaviour of proteins in RSBM, especially in the presence of the test protease.
Tuesday, 20th September 2016.
Birth type (BT) and rearing type (RT) influence lamb growth and development from zygote to birth (for BT) and from birth to adult (for BT and RT). BT and RT also constitute an environment that influence the expression of early growth of Merino lambs and its influence might continue along trajectory of their lives. There is genetic variation in growth rates of animals and this variation may change over the growth path of animals, with different genes being expressed at different times during development.
This can be explored at a quantitative genetic level by estimating the genetic correlation between growth traits measured at different ages. Random regression models (RRM) have been used to analyse and describe the genetic variation over the growth trajectory of cattle, pig and sheep whereas this models have also been used to describe variation in test day yield along the lactation curve. Genotype by birth or rearing type interaction can be identified when breeding values for growth expressed in singles rank differently than breeding values expressed in twins.
This study explores the genetic model underlying the growth path singles and twins and how the pre- and post-natal environment affects the expression of genetic merit for different parts of the growth curve.
Tuesday, 13th September 2016.
Rapeseed production, including canola varieties, ranks second among oilseed crops worldwide. Canola seed production in Australia has grown from 1.9 to 3.6 million metric tons over the past 5 years. Canola meal (CM) is a co-product of the canola seed-crushing industry and is widely used as a secondary protein source along with soybean meal (SBM) in broiler diets. It has a good balance of essential amino acids and is higher in methionine and cysteine on a protein basis than SBM. However, CM energy and digestibility of amino acids is typically lower than SBM. Anti-nutritional factors such as glucosinolate and sinapine may also restrict its use to less than full replacement of SBM in poultry diets. The fibre components of CM have been shown to be negatively correlated to energy digestibility of the meal.
The outlined project has examined variation in feeding value of experimentally produced and commercial sources of Australian canola meals. The project has endeavoured to develop commercial ties with the crushing industry to evaluate opportunities for product improvement. Commercially acceptable methods to enhance nutritional value of CM have been examined. These include modifications of processing parameters, the use of newly developed commercially available enzymes and the possibility of using extra supplemental amino acids in CM-based diets for broiler chickens.
Tuesday, 30th August 2016.
Resilience is the ability of an animal to cope with short-term challenges and return to its pre-challenge state. Strategies aiming to identify and select resilient animals that can better cope with our production systems are expected to improve both the productivity and welfare of our livestock. This thesis aims to better understand the resilience phenotype in livestock and identify potential measures of resilience which are practical and applicable on farm. The first experiment conducted as part of this thesis aimed to better understand the relationships between the different components of resilience in sheep.
Tuesday, 21st June 2016.
Infectious bursal disease is first reported in 1957 in Gumboro area, Delaware, USA and disease is caused by IBDV. Since then IBDV was distributed rapidly throughout the world. The current reach study was designed to test following broad objectives:
- Define differences between Australian classical and variant strains,
- Determine independent effects of age resistance and presence of maternal antibodies,
- Detection of IBDV vRNA in environmental samples,
- Test transmission of IBDV by contaminated dust,
- Determine temperature-time combinations required to inactivate IBDV in heaped litter.
Tuesday, 14th June 2016.
Cereal grains typically constitute the largest proportion of practical diets for poultry. Wheat is the predominant cereal grain used by the poultry industry in Australia and Europe. Wheat, like most temperate cereal grains, contains high levels of insoluble non-starch polysaccharides (NSP), in addition to phytic acid, the main reservoir of phosphorus in grains. Diets for meat chickens are routinely supplemented with microbial enzymes targeting NSP and phytic acid, and new enzyme products are continuously being produced and tested for introduction into the market. This presentation will outline a project that was developed to evaluate the response of poultry on diets containing wheat, maize or sorghum. Preliminary results that have been obtained from the trials on wheat will be presented.
Tuesday, 31st May 2016.
Mitochondrial quantification was performed in the shell gland of laying hens treated with nicarbazin using a quantitative PCR assay. Furthermore, expression of seven genes associated with protoporphyrin IX (PP IX) synthesis and/or deposition was examined in order to assess whether the treatments can lead to differential expression of the genes. The results showed that the mitochondrial concentrations per cell were significantly lower in the nicarbazin-fed group at 15 hr post-oviposition time. In the control group, the expression of ALAS1, FECH and SLC25A38 were significantly different at different stages post-oviposition. In the nicarbazin group, the expressions of all genes except CPOX were significantly different at different stages of post-oviposition. Comparing the effect of drug on the expression stabilities of the genes, ALAS1 was significantly down regulated in the nicarbazin fed groups. The PP IX content per gram of shell gland tissue was significantly lower (P<0.05) in the nicarbazin-fed birds compared with the control group. The amount of PP IX in whole eggshell decreased with day effect in the nicarbazin group, in a linear pattern, but it remained constant in the control group. However, egg weight and shell thickness were not significantly different between the control and nicarbazin-fed groups. It can be concluded that the mitochondrial concentrations in the shell gland were altered by nicarbazin only at 15 hr post oviposition, and the expression of some genes associated with PP IX synthesis and/or deposition were affected by post-oviposition time. The expression level of ALAS1 gene was significantly down regulated in the nicarbazin-fed groups that resulted in lower production of PP IX appeared in the eggshells.
Tuesday, 24th May 2016.
Hanwoo cattle are known for their high meat quality, particularly their high marbling (intramuscular fat) ability compared to most other breeds. Meat flavor and tenderness are largely determined by intramuscular fat composition, muscle fiber characteristics and connective tissue structures. All of these factors differ largely between muscle types but it is not well known how this differentiation occurs and what are the genes and pathways that regulate the process. To better understand the myogenic processes involved in differentiation of Hanwoo muscle types we performed a time-series RNA-seq experiment to measure transcriptome expression levels during the development of muscle satellite cells (MSC) in Longissimus dorsi (LD) and Semimembranosus (SM).
Free-range systems are perceived to improve hen welfare through providing outdoor access but not all hens choose to use the range. The outdoor range is typically more spatially complex than indoor environments, thus outdoor-preferring hens might have improved cognitive abilities compared to indoor-preferring hens during cognitive tests. Indoor-preferring and Outdoor-preferring hens were assessed with a novel detour-reaching task and in a reverse T-maze. Indoor hens showed slower latencies to learn indicating poorer cognitive abilities compared to Outdoor hens but differences may be modulated by reducing fear through habituation to novel environments.
Tuesday, 5th April 2016.
New technologies are presenting opportunities for remote sensing of core body temperature in animals. If a protocol can be established, then these technologies can be used to monitor fever and inflammation in livestock in the paddock. To test for suitable implant sites, eleven crossbred ewes were implanted with temperature sensing microchips positioned in the neck muscle and tail regions, sites potentially suitable for remote temperature monitoring. Temperature measurements were taken at regular intervals from the microchips and from vaginal (core) temperature using iButton and thermocouple sensors. Temperature change was recorded over baseline and treatment periods where sheep were exposed to challenges designed to increase (i.v. lipopolysaccharide) and decrease (cold water gavage tube) core temperature. Results were analysed and compared between traditional temperature measurement methods and microchips for ability to reflect core temperature and changes in core temperature.
Tuesday, 15th March 2016.
Gastrointestinal parasites are one of the most important health problems affecting sheep. Breeding sheep for enhanced resistance has been suggested as a viable method of parasite control, and the identification of genes for parasite resistance would greatly accelerate the genetic improvement. The aim of the study was to identify genomic regions underlying variation in parasite resistance in a large population of Australian sheep, using Genome-wide association studies (GWAS) and regional heritability mapping (RHM) approaches.
Tuesday ,15th March 2016.
With the availability of the Affymetrix 90K buffalo SNP Chip, this thesis will explore the use genomic data in a dairy buffalo breeding program. I will first look at the structure of the genetic diversity of buffalo populations. I will then identify SNPs and candidate genes associated with milk traits using genome-wide association study. Subsequently, I will test the accuracy of genomic prediction for milk traits. Finally, I will look into the implementation and optimisation of a dairy buffalo breeding program using genomic selection.
Monday, 7th March 2016.
Dr Jean Noblet worked at INRA (for "Institut National de la Recherche Agronomique") in France from 1977, most recently as Director of Research. He is located near Rennes (Brittany). He has "Ingénieur Agronome" and PhD degrees from the National Institute of Agronomy in Paris and the University of Paris. In 2000, he received the "Non-ruminant Nutrition Award" of the American Society of Animal Science. His research has concerned energy and protein nutrition of swine and, more recently, of poultry and calves with achievements in calorimetry methods, evaluation of energy content (net energy concept, for instance) of pig feeds, factorial quantification and modelling of energy requirements in pigs, calves or poultry and thermoregulation of pigs. He was the Editor-in-Chief of Animal journal from 2012 to 2014. He has authored or co-authored about 200 reviewed papers or book chapters, about 400 communications and 2 software applications on pig production: InraPorc and EvaPig. He retired from INRA at the start of 2016.
Bruno will speak about a collaboration initiative between Australian and New Zealand institutions, as well as private organisations, interested in quantifying production and economic benefits of recording and selection in commercially managed sheep flocks of multi-tiered breeding schemes.
Tuesday 9th February, 2016.
Free-range egg production is rapidly growing in Australia with an estimated retail value market share of 48 %. Laying hens exposed to pasture range may experience reduced performance, poor enteric health and increased mortality. In addition, egg quality can also be affected, indicated by the increased number of damaged and misplaced eggs as well as decreased egg shell quality. These effects may be related to excessive fiber digestion and reduced nutrient uptake. The addition of multi-enzymes or organic acids to free-range layer diets may improve the digestion of nutrients, thus increasing performance, gut health and egg quality. We conducted a study to investigate the effect of range types and feed additives on performance and egg quality and performance of ranging laying hens.
Tuesday 2nd February, 2016.
Supplementing ruminants with dietary nitrate reduces methane emissions, but can expose animals to nitrite toxicity risks. This study investigated if adaptation to dietary nitrate and supplementation of fermentable energy sources (glucose or glycerol) reduce accumulation of nitrite in vitro. There was no effect of additional energy sources on nitrite accumulation, adaptation of rumen fluid donors to dietary nitrate even increased accumulation of nitrite. In vivo verification is needed to assess the role of adapting ruminants to nitrate supplementation on risks of nitrite toxicity.