Dr Ken Ng, Jenny, Tran & Debbie Zhengyan Xu
Dr Ken Ng with Jenny Tran and Debbie Xu, Pork CRC supported students in his Master of Food Science course at The University of Melbourne.
Pork CRC Project 3B-112, ‘Nutritional composition of pork’
Debbie Zhengyan Xu and Jenny Tran, The University of Melbourne
Supervisor: Dr Ken Ng, The University of Melbourne
Fresh approach to popular pork cuts
Earlier this year Pork CRC awarded Debbie Zhengyan Xu and Jenny Tran honours scholarships, each worth $10,000, as part of Pork CRC Project 3B-112, ‘Nutritional composition of pork’.
Their supervisor is Dr Ken Ng at The University of Melbourne, where he coordinates the Master of Food Science course.
Pork CRC’s Program 3, ‘Healthy Pork Consumption’, is all about developing quality assessment tools for pork in domestic and international markets, plus investigating the inherent properties of pork that contribute to improved consumer health when pork is consumed as part of a total diet. The latter investigation is covered in Pork CRC Subprogram 3B.
Debbie Xu is a graduate student at The University of Melbourne, where she is studying a Master of Food Science. She was born in China and came to Australia at 18 to study. Two years later she completed a Diploma course in Hospitality Management at Chisholm Institute of Technology, Melbourne. After a one year stint as a cook, Debbie decided to further advance her education.
She received her Bachelor Degree in Science and Postgraduate Certificate in Nutrition and Dietetic from Curtin University, Perth, where in her last year of study she had internships, as a student dietician, with National Heart Foundation WA division, Royal Perth Hospital and Sir Charles Gairdner Hospital.
After discovering her passion for food science and research, she returned to Melbourne to continue her study in food science. She currently works part time for a food formulation company, The Product Makers (Springvale, Melbourne), as a laboratory assistant and also as a student library assistant with the ERC Library, The University of Melbourne.
Jenny Tran is currently completing her Master of Food Science at The University of Melbourne.
She has experience in product development, participating in this year’s Australian Institute of Food Science and Technology (AIFST) competition for innovative products. The team Jenny worked with developed a mochi coated protein ball that was then marketed to a health conscious audience.
Jenny is also a founding member of the Graduate Agriculture and Food Society at The University of Melbourne, which helps connect postgraduate Agriculture, Food Science and Packaging students to the industry. As well as her studies, Jenny works in the retail sector, where she enjoys communicating and engaging with consumers.
Jenny will analyse the lipid composition of three popular fresh pork cuts within Australia, as provided by APL.
Debbie will analyse proximate composition and iron content of three popular fresh pork cuts within Australia, as provided by APL.
Their analysis will profile the fatty acids, as well as provide information on the total saturated and unsaturated fatty acids, and protein and iron content.
The project will use validated sampling and analytical techniques to ensure cuts are nationally representative and sourced from a range of retail outlets.
It is anticipated that their research will provide the data to update existing Australian compositional databases and the Australian pork industry’s internal food composition databases to identify research and development investments into nutrition and health.
Ken Ng is a Lecturer in Food Chemistry in the Faculty of Veterinary & Agricultural Sciences at The University of Melbourne.
He has a PhD in biochemistry and researches the nutritional profiles of foods, chemistry and biochemistry of plant antioxidants and anti-cancer properties of organic Selenium.
Dr Ng has also researched formulation approaches to pharmaceutical delivery of chemically labile antioxidants (Monash Uni), biosynthesis of lipophosphoglycans from the protozoan parasite of human, Leishmania, biosynthesis of beta(1-3)glucan (LaTrobe Uni) and on the biosynthesis of hyaluronic acid (Uni Chicago, USA). Dr Ng has more than 35 research publications and is a former recipient of an ARC Research Fellowship and ARC research grants.
Coordinator of the Master of Food Science course, Dr Ng also coordinates and teaches in the undergraduate subjects FOOD20003 Food Chemistry, Biology & Nutrition and FOOD30010 Functional Foods, and the Masters subjects FOOD90022 Food Chemistry and FOOD90025 Health Aspect in Functional Foods.
Further information: Dr Ken Ng, email email@example.com
First published in APN Sept 2015
Pork CRC Industry Placement, Predicting the eating quality of pork, Linley Valley Pork.
Supervisor: Ron Penn, Craig Mostyn Group/ Linley Valley Pork.
Suckling Pig Placement an Industry Plus
Amy Suckling graduated with a Bachelor of Science, majoring in Molecular Biology and a Bachelor of Animal Science (Hons) from Murdoch University, Western Australia.
During her studies, she participated in the Intercollegiate Meat Judging Competition where she developed a greater appreciation and understanding of meat science, visual meat quality assessment and the MSA grading system. Her interest in pigs evolved from work experience placement at an intensive breeding unit in WA, where she was exposed to various aspects of pig production.
Amy’s interest in pigs and meat science led to the development of an honours project, with assistance from Professor John Pluske, Dr Cameron Jose and Dr Peter McGilchrist at Murdoch University. The project aimed to investigate differences in the meat quality of free-range-bred pigs from different finisher housing systems at a grower farm in WA. To support this project Amy applied for and gratefully received, a Pork CRC Honours scholarship under Pork CRC Program 3 (‘Healthy Pork Consumption’). The project involved taking small muscle samples and measuring the pH and colour of pork from the hanging sides at the Linley Valley Pork abattoir. Biochemical analysis of the meat samples in the laboratory at Murdoch University measured the glycogen and lactate content of the pork. While the project’s results did not definitively determine whether differences in finisher housing impacted on meat quality, it found that higher glycogen stores in free-range-bred pigs before slaughter correlated with a faster rate of pH decline in pork.
Through exposure to the pork industry via her honours project, the Pork CRC and Murdoch Intercollegiate Meat Judging Team, Amy met people in industry and after attending networking occasions and upon completion of her degree and honours project, an opportunity arose to accept a position as Animal Scientist at the Linley Valley Pork abattoir. Linley Valley Pork is a division of Craig Mostyn Group, an Australian owned diversified food and agribusiness with operations in WA, Tasmania and Victoria. Branches include Meat and Livestock, encompassing the Linley Valley Pork and CM Farms operations; Rendering and Protein, consisting of Talloman and Protein Trading divisions and CM Food, which includes CM Tasmania Seafood, Jade Tiger Abalone and Fresh Produce divisions.
Support was sought from the Pork CRC to involve Amy in the Industry Placement Program under Program 3, which she has now been a part of since mid-2013. Amy works alongside and is mentored by Dr Megan Trezona of the Department of Agriculture and Food Western Australia at the Linley Valley Pork abattoir, with work largely focusing on meat quality research. In her role as Animal Scientist, Amy assists with coordination and delivery of contracted commercial and public sector projects for Linley Valley Pork, as well as other assorted reporting duties.
Projects she has assisted with since beginning her industry placement have included the Pork CRC project 3A-109 Eating Quality Validation study by APL’s Heather Channon. The Linley Valley Pork component of the project involved electrical stimulation of pigs on the bleed chain and collection of a large quantity of silverside and loin samples for sensory analysis. Other Linley Valley Pork projects have been on seasonal meat colour and improving pig welfare in lairage.
Although Amy is largely focused on meat quality in her role, work with Linley Valley Pork also extends to assisting with the coordination of external projects that utilise CM Farms facilities. This has included recent work by Dr Shannon Dundas of Murdoch University, who is investigating the extent of fox predation on free-range pig farms and alternative baiting methods for fox control.
Recently, Amy has been involved in the Western Australian Pig Industry Event Planning Group, initiated by Dr Bruce Mullan of DAFWA and Westpork’s Richard Evison, President of the West Australian Pork Producers Association, to develop programs for industry events that span a range of relevant and applicable topics for WA pork producers. The group consists of Emalyn Loudon of Westpork (Group Chair), Kate Gannon of Portec Veterinary Services and Dr Jae Kim of the Pork Innovation Group at DAFWA. The Planning Group has so far assisted with the organisation and planning of the WA Pork Industry Day in October and Industry Discussion Topics presented in early December, 2104.
Amy considers herself fortunate to have found a niche that combines her love of working with pigs and laboratory work. In the future, she hopes to increase the time spent on farm, while also developing her interests in genetics and pathology in new projects.
Amy with Pork CRC Chairman Dennis Mutton and APL’s Darryl D’Souza and Robyn Terry
First published in APN, Jan 2015
Benchmarking meat quality parameters of high integrity pork between conventional and deep litter housing systems
In 2009 when a Pork CRC supported 4th year animal science honours student at WA’s Murdoch University, Amy received a trophy and $2000 cheque for winning the Pork CRC Award for best presentation at APSA for her research project into minimising boar taint. Pictured above with Dr Bruce Mullan (centre) of DAFWA and Pork CRC Board Member, Professor John Pluske of Murdoch University.
Masters student, School of Land and Environment, University of Melbourne
Supervisors: Prof Frank Dunshea, University of Melbourne, Dr Darryl D’Souza, APL and Dr Robert Smits, Rivalea Australia
How housing might matter to meat
Amy Lealiifano received a Pork CRC Honours scholarship in 2009 to look into altering the timing of the second immunocastration (Improvac) vaccination as part of the final research component for her Bachelor of Animal Science at Murdoch University.
Currently working in Rivalea Australia’s Research and Innovation Meat and Processing Department, Amy is completing a Masters, investigating the different technical meat quality parameters between conventional and deep litter housing systems.
The focus of her research, conducted under Pork CRC Program 3, is to determine and quantify the impact of housing and carcass weight on the different meat quality parameters and also to identify meat quality pathways and the interrelationships that affect final pork quality from carcasses sourced from conventional and deep litter produced carcasses and of two different weights.
Meat quality of pork is complex and affected by a number of on-farm and post-slaughter factors. These multifactorial factors are interrelated and combine to create a meat quality pathway. Previous research has determined and documented the importance of a number of pre and post slaughter management factors on pork quality performance. A number of these production and slaughter factors have been identified as potential risk factors to achieving high quality pork. Consequently, these factors can be manipulated to improve specific quality attributes.
Currently, most research involving individual effects has been conducted on conventionally raised pigs housed indoors on concrete-slatted flooring. However, with the industry changing to an increased focus on housing, particularly alternate housing systems, there has been greater use of deep litter systems to grow pigs to slaughter. There is also increasing pressure to produce pigs of a heavy carcass weight (95-110 kg) to minimise farming and processing overhead costs and therefore remain internationally competitive. Most previous research concerning the individual pre and post slaughter effects on meat quality measurements have been conducted on lighter carcasses (65-75 kg).
Pork is part of a highly competitive food market where future success depends on understanding consumer perception of quality. Today’s consumers are more highly informed than ever before and have an increased awareness of meat quality, including objective and sensory characteristics Additionally, as consumer expectations of meat quality grows, there is an obligation for quality control and paddock to plate quality standards to be present and active at the level of pre-slaughter conditions, slaughtering, meat cutting and distribution. By adopting an approach that identifies meat quality standards, based on understanding the variables which exist due to different farming systems and abattoirs, the meat quality from pigs reared under conventional or deep litter production systems, is likely to improve.
Boar taint is remains the biggest limitation to the consumption of and demand for Australian pork.With the industry moving toward castrates with Improvac vaccinated males to eliminate boar taint, improving the consistency of high quality pork cuts, especially those from the loin and the leg, is extremely important. Acceptability of these cuts, as being consistently high quality, will largely determine what the consumer will pay for pork relative to other meats and this impacts the value of the carcass to the processor and ultimately the producer.
Identifying and improving meat quality standards for conventional and deep litter farm systems in light and heavy carcasses are essential to ensure pork product quality is enhanced. The information contributed by this Pork CRC supported research is expected to reduce pork failure rates from 30% to below 10% by improving colour, tenderness and water holding capacity of meat and minimising variation due to pre and post slaughter management strategies. Data from this study will provide a meat quality benchmark on a large scale and identify the interrelationships that affect pork quality from carcasses sourced from conventional and deep litter housed pigs over three different weights. This will also enable strategies to be developed that can be applied to pigs from different farm sources to overcome predicted low meat quality.
Contact: Amy Lealiifano, email ALealiifano@rivalea.com.au
First published in APN Sept 2014
A comparison between a higher pork-protein, lower-carbohydrate diet and a lower pork-protein, higher-carbohydrate diet, combined with regular moderate intensity exercise on diabetes control, cardiometabolic health, food cravings, cognition and psychological wellbeing in adults with Type 2 diabetes mellitus , part of Sub Program 3B – Inherent Properties of Australian Pork to Enhance Consumer Health.
Pork CRC PhD candidate – Nutritional Physiology Research Centre (NPRC), University of South Australia
Supervisors: Dr Karen Murphy and Professor Jon Buckley (University of South Australia) and Associate Professor Grant Brinkworth (CSIRO)
Possible positive role for pork in diabetes drama
Having completed a Master Nutrition and Dietetics degree, Nerylee Watson has worked as an Accredited Practicing Dietitian in the area of diabetes for six years in hospital, community and private settings.
She is now doing a Pork CRC supported PhD (within Pork CRC Project 3B-102)related to Type 2 diabetes mellitus, the fastest growing chronic disease in Australia. Poorly controlled blood glucose levels are responsible for substantial morbidity and mortality resulting from cardiovascular disease, diminished cognitive function (particularly verbal and visual memory, psychomotor skill and executive function) and a poorer quality of life. The cognitive decline and psychological distress associated with diabetes can lessen an individual’s ability to self-manage their disease, leading to an increased risk of developing complications. Achieving and maintain a healthy weight through diet and physical activity are the cornerstones for the management of glycaemic control in Type 2 diabetes irrespective of the need for medication.
Although the most beneficial dietary pattern to achieve glycaemic control is unclear, according to Nerylee there is some evidence supporting energy-restricted, high-protein, low-carbohydrate diets for weight loss, improved glycaemic control, cardiovascular health and cognitive function. Red meat tends to be the protein source in published studies, however previous research by the NPRC has demonstrated that lean fresh pork is equally as beneficial as beef and chicken in reducing obesity and improves body composition and cardiometabolic health in healthy individuals (Pork CRC Project 3A-111). The National Health and Medical Research Council is reluctant to recommend high protein diets for the management of Type 2 diabetes due to the limited supporting evidence available in this population.
Nerylee’s Pork CRC PhD project aims to compare two levels of pork consumption in the form of a higher pork-protein, lower-carbohydrate diet and a lower pork-protein, higher-carbohydrate diet combined with moderate intensity aerobic exercise in an energy restriction, weight loss phase and an energy balance, weight maintenance phase in a Type 2 diabetes population. There are very few studies that have investigated whether the improvements shown during weight loss continue during a stable weight phase, in the absence of any further weight loss, in a Type 2 diabetes population which would reflect the potential longer term advantages of adherence to this dietary pattern. The primary outcome for this study is glycaemic control (HbA1c), with secondary outcomes of body composition (weight loss, fat mass, lean mass, waist circumference), cardiovascular disease risk factors (blood pressure, blood lipids, glucose, insulin and C – reactive protein), food cravings, cognitive performance and psychological well-being.
Sixty one participants who met the eligibility criteria were enrolled and randomly allocated to one of the two energy matched diets. Volunteers will follow their diet throughout the weight loss phase (0-12wks) and the weight maintenance phase (12-24wks). Lean fresh pork is the major protein source and volunteers will consume a variety of pork cuts four times a week. Throughout the study, participants are required to undertake aerobic exercise at a moderate intensity, for a minimum of 30 minutes five times a week (150 minutes/week) and maintain a physical activity log. Volunteers will attend the NPRC at weeks 0, 12 and 24 for anthropometric measurements (including a DEXA body composition scan), fasting blood tests, cognitive function testing and to complete psychological well-being questionnaires. At the end of each of the three clinic visits, and fortnightly throughout the study, participants will see a Dietitian for dietary advice and return their food diaries to measure compliance. Data collection will be completed in 2014.
Results of this study are of high relevance to the pork industry as it will provide information on several health outcomes following pork consumption, including diabetes control, cardiovascular risk factors, weight loss, weight maintenance and cognition and psychological wellbeing. Collectively, these outcomes have not been studied previously in this type of dietary intervention trial, according to Nerylee. It will also provide information to consumers and health care providers that lean pork can be used as a protein source in everyday balanced diets, as well as dietary meal planning for weight loss and diabetes control.
Contact details: Nerylee Watson, email: firstname.lastname@example.org
First published in APN Jan 2014
Get Small farms article on Nerylee’s work available here
PhD topic: Producing quality pork by optimising the production of male pigs immunised against gonadotrophin releasing factor (GnRF), part of Pork CRC Subprogram 3A – Optimal pork quality for multiple markets
Pork CRC and APL PhD Candidate, School of Land and Environment, University of Melbourne.
Supervisors: Dr Bruce Mullan, Department of Agriculture and Food WA (DAFWA), Professor Frank Dunshea, University of Melbourne, Dr Ian Bland, University of Melbourne
Boaring approach to taste of success
Karen Moore is in her second year of a PhD investigating the production of quality pork by optimising the production of male pigs immunised against gonadotrophin releasing factor (GnRF) i.e. pigs that have received Improvac®. She has a Bachelor of Science in Agriculture (Hons), is supported by Australian Pork Limited and her research is conducted under Pork CRC Program 3, Healthy Pork Consumption. From a pig farming background, Karen is a Research Officer in the Pork Innovation Group at the Department of Agriculture and Food WA where her recent work has focused on nutrition and meat quality in grower-finisher pigs.
Boar taint, which refers to the urine or perspiration-like odour that occurs in carcases of some entire males, is a significant cause of consumer complaints about pork. Immunising entire males against gonadotrophin releasing factor (GnRF) is an effective strategy to eliminate boar taint and a welfare friendly alternative to physical castration. The vaccine is administered relatively close to slaughter, allowing the pig to grow as an entire male with associated positive effects on growth rate and carcass leanness. After the secondary vaccination, any taint substances present are progressively metabolised, but there is an increase in feed intake and backfat thickness.
Little work has been done with pigs that have received Improvac® to look at their nutrient requirements. It is important that pigs are fed the optimum lysine level to ensure lean growth is maximised and feed costs are minimised. It is also important that lysine requirements for immunised males are appropriate in order to benefit from the two distinct phases i.e. the benefits of entire male production and immunisation against GnRF. This project aims to determine the dietary lysine requirements of immunised males. It was found that pigs that had received Improvac® should be fed as entire males until at least two weeks after the second vaccination, after which the available lysine to energy ratio can be decreased.
Although Improvac® is very effective at eliminating and controlling boar taint, the associated increase in fat deposition and feed intake has potentially limited its uptake in the Australian industry because of the price penalties on fat carcases. This project will investigate how body composition and certain physiological measures change following the second vaccination of Improvac®. By identifying the changes and their timing we will be in a better position to identify management strategies that could improve carcase quality and eating quality of pork, without any major effect on the cost of production.
Following on from determining the nutrient requirements of immunised males and investigating body composition and physiological changes, the final aim of this project is to use the information to develop on-farm management strategies to optimise production of immunised males.
By developing on-farm management strategies to overcome the disadvantages associated with the production of immunised males, it’s hoped there will be increased uptake of immunisation against GnRF by the Australian pork industry.
Increased use of Improvac® will potentially help reduce the incidence of consumers having a negative pork eating experience due to boar taint.
Contact Karen Moore, email Karen.email@example.com
First published in APN May 2014
PhD topic – Predicting the eating quality of pork, part of Pork CRC Subprogram 3A – Optimal pork quality for multiple markets
Supervisors: Prof Frank Dunshea, University of Melbourne and Dr Darryl D’Souza, APL
Consistently delivering great tasting, tender and juicy pork to enable consumers to have enjoyable pork meals, no matter what the occasion, is the overall outcome of current eating quality research being supported by the Pork CRC and Australia’s pork industry. Although taste has been shown to be the biggest single driver of consumer satisfaction and repeat purchase of pork, tenderness and juiciness are also very important. Meeting this outcome may appear straightforward, but pork eating quality can be influenced by many factors – from on-farm, all the way along the supply chain to cooking by consumers. Overcooking of pork can detrimentally affect eating quality, making it tough and dry.
Although many studies have been conducted to understand the effect on pork eating quality of different production, pre- and post-slaughter and cooking factors, these outcomes have not previously been integrated into an eating quality system. Predicting the eating quality of pork is therefore the focus of Heather Channon’s PhD program through the University of Melbourne, supervised by Professor Frank Dunshea and Dr Darryl D’Souza, with funding from the Pork CRC and APL.
Heather’s research, which is part of Pork CRC Program 3A Optimal Pork Quality for Multiple Markets, aims to develop a non-prescriptive, cost-effective, cuts-based eating quality systemthat can reduce the fail rate for consumer acceptability of Australian pork to less than 10%. The term ‘fail rate’ refers to the percentage of consumer assessments of pork for quality grade that are rated as unsatisfactory (1) or below average (2) on a five point scale for quality. Previous APL research identified that about 30% of generic Australian pork failed to meet consumer expectations for quality. This work builds on Heather’s previous work
The first stage of Heather’s research program involved collating previous eating quality research conducted in both Australia and overseas and compiling an extensive database and analysis of this dataset to identify key pathway factors that can influence tenderness, juiciness and flavour of pork, plus any knowledge gaps.
Many of these studies used the loin muscle, cooked as a steak or roast and this needs to be addressed, according to Heather, so that a cuts based system can be developed for the Australian industry.
Pork CRC funded research has aimed to fill knowledge gaps – one study, now completed, determined the effect of gender (entire male, surgical castrate and female), ageing period (two and seven days post-slaughter), endpoint temperature (70 or 75°C), cut type (loin, silverside and shoulder) and cooking method (roast and stir fry for all cuts and steak for the loin only).
Fail rate of pork from entire males was higher than from surgical castrates, with females intermediate. Flavour, juiciness and overall liking scores were also lower for entire males compared with surgical castrates, with scores for females between these two genders. Ageing for seven days was not long enough to result in eating quality improvements compared to two days, unlike other studies where beneficial effects of ageing for seven days on eating quality have been reported. Cooking pork loin steaks to 75°C compared to 70°C dramatically increased the fail rate from 22% to 36%. Lowest fail rates were found for the shoulder stir fry (5%), shoulder roast (12%), loin stir fry (15%), loin roast (19%), loin steak (30%) and silverside (36%). The final report for this study can be found here.
It is clear that more work is needed to improve the eating quality performance of these cuts. A similarly designed study involving immunocastrates and entire males has also been conducted and outcomes will be provided shortly. A recently completed Pork CRC study (3A-105) aimed to evaluate whether nutritional management/age at slaughter and ageing period influenced pork eating quality of loin and silverside muscles from female pigs. The final report for this study is available here.
The next phase of this work, being supported by Pork CRC in 2013/14, will involve a validation study to refine proposed eating quality pathways, with the co-operation of a number of supply chains. To further reduce the fail rate of pork, other pathway interventions will be explored e.g. aitchbone hanging to tenderstretch the hindquarter, electrical stimulation, ageing period and moisture infusion.
Heather Channon is Manager, Product Integrity in the Research and Innovation Division at Australian Pork Limited and can be contacted on email heather.channon@ australianpork.com.au or mobile 0423 056 045.
First printed in APN Aug 2013
Project supervisors: Frank Dunshea (University of Melbourne), Darryl D’Souza (APL) and Brian Leury.
Pork CRC Post Grad Project as part of Project 3A – 103: Effects of various eating quality pathway factors on pork quality
Our primary hypothesis was that dietary lecithin could improve pork objective quality by reducing the contribution of intramuscular collagen to meat toughness.
We also hypothesised that lecithin could improve pork fatty acid profile and reduce total cholesterol.
In terms of growth performance, it’s possible that dietary lecithin could enhance feed conversion ratio (FCR) and growth rate in finisher pigs because of lecithin’s emulsifying properties.
The first animal experiment explored the effect of dietary lecithin on pig growth performance, carcass quality, meat quality and objective quality, especially in relation to intramuscular collagen in finisher gilts. The influence of dietary lecithin on pork fatty acid profile and cholesterol level were also investigated. Following promising results on the effect of a lower dose of dietary lecithin (4 g/kg) in the first experiment, another two investigated the use of the lower dose of dietary lecithin on other sexes of pigs, with particular emphasis on the immunocastrated (IC) pigs.
The second animal experiment involved a 2 x 2 factorial experiment, with the respective factors being dietary lecithin (0 or 5 g/kg) and sexes i.e. gilts and IC pigs immunised against gonadotrophin-releasing hormone (Improvac®). The third animal experiment involved a 2 x 3 factorial experiment, with the respective factors being dietary lecithin (0 or 8 g/kg) and sex i.e. gilts, IC pigs and entire male (EM) pigs. The interpretation of the results enabled a better understanding of the mechanisms involved in the improvements of FCR, dressing percentage and pork chewiness in pigs fed dietary lecithin.
We confirm that the mechanism involved in reducing pork chewiness (P=0.049) from pigs fed dietary lecithin in this experiment was through reduction of muscle hydroxyproline content (P=0.008). Regulating collagen synthesis at the molecular level was clearly involved in reducing hydroxyproline content as indicated by the down-regulation of Type I and III collagen precursor gene expressions in muscle from gilts fed dietary lecithin (P<0.05, respectively). These observations are further supported by evidence of simultaneous decrease in gene expression of the gene responsible for collagen synthesis, namely α-subunit prolyl-4 hydroxylase in muscle from pigs fed dietary lecithin (P=0.057).
However, we were unable to reproduce consistent results in the later animal experiments involving additional sex groups of EM pigs and IC pigs. Data from these experiments consistently showed increased growth rate in IC pigs before slaughter. The third experiment identified that IC pigs had the lowest shear force values, compared with gilts and EM pigs (P=0.042), hence we suggest that increased growth rate in IC pigs may presumably increase intramuscular collagen solubility, thus improve meat texture.
In terms of growth performance, although not consistent across experiments, our results indicate the effect of dietary lecithin on pig feed intake, FCR and dressing percentage was reasonable. In the first experiment, dietary lecithin increased dressing percentage in gilts (P=0.009). A clearer implication of dietary lecithin as an emulsifier was observed when there was an improvement in FCR of gilts and EM pigs fed a high level of dietary fat (4.6 % tallow), plus dietary lecithin (P=0.006). This suggests the influence of dietary lecithin in improving FCR was through enhanced tallow digestibility. The final experiment showed increased feed intake in pigs, especially gilts, fed dietary lecithin (P=0.04), but dressing percentage and FCR were not affected by dietary lecithin (P>0.05, respectively).
In terms of pork nutritional values, dietary lecithin produced a superior polyunsaturated to saturated fatty acid ratio (PUFA: SFA) (P=0.002) of more than 0.5, which is more than the minimum (0.4) recommended values for the human diet. Dietary lecithin also improved the fatty acid profile of pork to be more favourable for cardiovascular health, as evidenced by reduced level of detrimental saturated fatty acids (i.e. myristic and palmitic) and increased beneficial unsaturated fatty acids (i.e. linoleic and α-linolenic, P<0.05, respectively). However, dietary lecithin had no effect on pork omega 6 to omega 3 ratio (n6: n3) or cholesterol level (P>0.05, respectively).
Collectively, the outcomes confirm dietary lecithin improves pork chewiness through reducing intramuscular collagen. These investigations provide an insight into the possible link between increased growth rate in IC pigs and pork objective quality.
It is necessary to confirm the impact of dietary lecithin and sex on pork objective quality using sensory panels. Overall, dietary lecithin improves dressing percentage as a consequence of increase in feed intake and better feed efficiency in finisher gilts. It remains necessary to continue exploring tallow digestibility in finisher pigs, which can influence FCR and dressing percentage in the particular role of dietary lecithin as an emulsifier.
The findings from this study also confirm that dietary lecithin can produce pork with a superior fatty acid composition, as evidenced by increase of PUFA: SFA ratio and reduction of myristic and palmitic fatty acids.
Contact details: Henny Akit, email firstname.lastname@example.org
First Published APN Nov 2012