Enhancing Omega-3 Long-Chain Polyunsaturated Fatty Acid Content of Dairy-Derived Foods for Human Consumption.

Omega-3 polyunsaturated fatty acids (n-3 PUFA) are termed essential fatty acids because they cannot be synthesized de novo by humans due to the lack of delta-12 and delta-15 desaturase enzymes and must therefore be acquired from the diet. n-3 PUFA include α-linolenic acid (ALA, 18:3n-3), eicosapentaenoic (EPA, 20:5n-3), docosahexaenoic (DHA, 22:6n-3), and the less recognized docosapentaenoic acid (DPA, 22:5n-3). The three long-chain (≥C20) n-3 PUFA (n-3 LC-PUFA), EPA, DHA, and DPA play an important role in human health by reducing the risk of chronic diseases. Up to the present time, seafood, and in particular, fish oil-derived products, have been the richest sources of n-3 LC-PUFA. The human diet generally contains insufficient amounts of these essential FA due largely to the low consumption of seafood. This issue provides opportunities to enrich the content of n-3 PUFA in other common food groups. Milk and milk products have traditionally been a major component of human diets, but are also among some of the poorest sources of n-3 PUFA. Consideration of the high consumption of milk and its processed products worldwide and the human health benefits has led to a large number of studies targeting the enhancement of n-3 PUFA content in dairy products. The main objective of this review was to evaluate the major strategies that have been employed to enhance n-3 PUFA content in dairy products and to unravel potential knowledge gaps for further research on this topic. Nutritional manipulation to date has been the main approach for altering milk fatty acids (FA) in ruminants. However, the main challenge is ruminal biohydrogenation in which dietary PUFA are hydrogenated into monounsaturated FA and/or ultimately, saturated FA, due to rumen microbial activities. The inclusion of oil seed and vegetable oil in dairy animal diets significantly elevates ALA content, while the addition of rumen-protected marine-derived supplements is the most effective way to increase the concentration of EPA, DHA, and DPA in dairy products. In our view, the mechanisms of n-3 LC-PUFA biosynthesis pathway from ALA and the biohydrogenation of individual n-3 LC-PUFA in ruminants need to be better elucidated. Identified knowledge gaps regarding the activities of candidate genes regulating the concentrations of n-3 PUFA and the responses of ruminants to specific lipid supplementation regimes are also critical to a greater understanding of nutrition-genetics interactions driving lipid metabolism.

Absence of a corpus luteum and relatively lesser concentrations of progesterone during the period of pre-ovulatory follicle emergence results in lesser pregnancy rates in Bos indicus cattle.

Concentrations of progesterone before AI have had variable effects on fertility in both Bos indicus and Bos taurus cattle. The aim of this study was to determine if fertility and concentrations of progesterone after AI were affected in Bos indicus females when pre-ovulatory follicles develop in the absence or presence of a corpus luteum (CL). Between 6.5-7.5 days after a synchronised oestrus, all follicles ≥4 mm in diameter were aspirated (Day 0) and cloprostenol was administered on Days 0 and 1 (LP4, n = 36) or on Days 4 and 5 (HP4, n = 40). Animals were inseminated on detection of oestrus until Day 9. Breeding continued using natural mating between Days 9 and 19, AI on detection of oestrus between Day 19 and 29 and natural mating between Days 29-90. Mean concentrations of progesterone were less on Days 2-4 in the LP4 compared to the HP4-treated animals but similar on Days 14 and 20. In the LP4- compared to the HP4-treated animals, the odds of being detected in oestrus and ovulating close to the first AI were similar, but odds of pregnancy to first AI (OR = 0.19, 95% CI 0.07 - 0.52) and after 1, 4 and 13 weeks of breeding were less (P ≤ 0.051). Absence of a CL and relatively lesser concentrations of progesterone during emergence of pre-ovulatory follicles resulted in lesser pregnancy rates to AI in Bos indicus cattle but did not affect concentrations of P4 after ovulation.

Effect of treatment of Bos indicus heifers with progesterone 0, 3 and 6 days after follicular aspiration on follicular dynamics and the timing of oestrus and ovulation.

Synchronisation of wave emergence is used to synchronise oestrus in cattle. The aim of this study was to determine if treatment with high concentrations of progesterone in Bos indicus heifers for 3 days would synchronise new wave emergence when treatment commenced at early, mid and late stages of follicular development. Heifers were treated with a sc silicone implant containing norgestomet from Days -7 to 9 and cloprostenol (IM) on Days -7 and -2. All follicles > 4 mm in diameter were removed by transvaginal follicular aspiration either on Days 0 (Experiment 1), 3 (Experiment 2) or 6 (Experiment 3). From Days 6 to 9 every heifer was treated with two intravaginal progesterone releasing inserts that each contained either no progesterone (Control, n = 8/experiment) or 3.12 g of progesterone (n = 8/experiment). Ovarian follicular development was monitored at least once daily following aspiration until oestrus and ovulation. In each experiment, treatment with progesterone significantly increased concentrations of progesterone in plasma from Days 6 to 9 compared to Control heifers. It also significantly delayed the day of emergence of the ovulatory follicle (1.6 ±â€¯0.6 vs 8.6 ±â€¯0.3; 4.1 ±â€¯0.1 vs 8.6 ±â€¯0.2; 7.0 ±â€¯0.0 vs 9.3 ±â€¯0.4, for Control vs progesterone treated heifers, respectively in Experiments 1 to 3) and the interval from implant removal to oestrus and ovulation. In conclusion, treatment with high concentrations of progesterone can synchronise wave emergence in Bos indicus heifers when administered at early, mid and late stages of follicular development.

Supplementation with plant-derived oils rich in omega-3 polyunsaturated fatty acids for lamb production.

In this report, an overview of the health benefits of omega-3 long-chain (≥C20) polyunsaturated fatty acids (n-3 LC-PUFA) and recent progress in using alpha linolenic acid (ALA) rich sources derived from oilseeds to enhance productive performance, n-3 PUFA profiles and sensory properties of lamb for human consumption is reviewed. Omega-3 LC-PUFA can prevent mental health issues and chronic human disorders including cancer, cardiovascular and inflammatory diseases. The median amount of n-3 LC-PUFA consumption is generally lacking in Western diets. More attention is now being paid to the use of innovative nutritional strategies to improve PUFA content in ruminants, which could subsequently increase the content of health-benefitting n-3 LC-PUFA for human consumption. The richest sources of dietary n-3 LC-PUFA are derived from marine products, while forage and oilseeds such as flaxseed, canola, and their oils are abundant in ALA. Numerous studies have shown that dietary ALA increases n-3 LC-PUFA levels of edible tissues. However, other studies concluded that ALA rich supplementation led to no differences in tissue FA profiles because of extensive biohydrogenation of dietary ALA, limited conversion from ALA to n-3 LC-PUFA and low incorporation of n-3 LC-PUFA into edible tissues. Generally, the inclusion of ALA rich sources in lamb diets potentially increases ALA content in lamb. It is proposed that supplementing ruminants with ALA-rich sources at or below 6% can promote n-3 PUFA profiles in lamb and is unlikely to have negative effects on feed intake, growth, carcass and sensory properties.

Chemical sterilisation of animals: A review of the use of zinc- and CaCl2 based solutions in male and female animals and factors likely to improve responses to treatment.

Chemical sterilisation can be used as an alternative to surgical castration in some circumstances. This review focuses on responses to treatment with zinc- or CaCl2-based chemosterilants, factors that have affected treatments and their potential use to sterilise female cattle. Successful treatment with a low incidence of adverse side effects in male animals has occurred with the use of zinc gluconate (ZG), neutralised in arginine and a 20% solution of CaCl2 in ethanol. Injection technique plays an important role in success. Less satisfactory results appear to occur following use in animals with relatively larger testes. In animals with relatively small testes adjustment of the dose according to testicular size appears to optimise results. The techniques appear to be most suited to population control strategies in companion animals where low cost treatment of animals in environments where surgical facilities and specialised aftercare are lacking. The need for careful administration and likely slower speed of administration compared to surgical castration are likely to hamper application within the cattle industries. Recently transvaginal, intraovarian administration of CaCl2 in ethanol has been shown to cause complete ovarian atrophy without apparent pain in some heifers, although variable responses were found. Chemical sterilisation can play a role in the sterilisation of animals but careful attention to dose, volume, chemical composition, administration technique are needed to avoid adverse side effects and variability in responses associated with some treatments. Application in female animals requires further study but CaCl2 in ethanol can potentially cause complete ovarian atrophy when administered to heifers.

Short-term supplementation with maize increases ovulation rate in goats when dietary metabolizable energy provides requirements for both maintenance and 1.5 times maintenance.

This study aimed to evaluate ovarian follicular dynamics in goats submitted to synchronization of estrus and supplemented with diets that differed in the metabolizable energy source and amount of energy. The experiment was carried out using 42 does allocated into three treatments, fed for 9 days with a ration providing 1.0 times maintenance containing maize (1 MM, n = 14) or without maize (1 M, n = 14) or a ration providing 1.5 times maintenance containing maize (1.5 MM, n = 14). Estrus was synchronized with two injections of cloprostenol given 7 days apart. Does were also treated with intravaginal progesterone inserts and eCG. The number of ovulations and size of the follicles were measured using ultrasonography on Days 10, 11, and 12 after the start of the dietary treatment. The interval to estrus and duration of estrus did not differ between treatments (P = 0.382). Does fed with 1 and 1.5 MM had a similar number of ovulations but a greater number of ovulations than goats fed with 1 M (P = 0.028). The mean number of small, medium, large, and total number of follicles on Days 10 to 12 of ultrasound evaluations did not differ (P = 0.204) between treatments, but mean numbers changed over time (P < 0.001). The mean frequency and amplitude of LH pulses and concentrations of glucose, insulin, leptin, and insulin growth factor-1 in plasma were not significantly affected (P > 0.258) by any of the treatments. In summary, the inclusion of maize in the ration can stimulate ovulation rate at maintenance level. Similar results between groups fed diets that included maize and provided metabolizable energy at 1.0 and 1.5 maintenance demonstrate that to increase the ovulation rate when synchronizing estrous cycles in does, dietary supplementation with maize can be restricted to provide a maintenance level of metabolizable energy only, which would reduce dietary costs.

Veterinary student attitudes toward curriculum integration at James Cook University.

The aim of this study was to investigate the attitudes of veterinary science students to activities designed to promote curriculum integration. Students (N = 33) in their second year of a five-year veterinary degree were surveyed in regard to their attitudes to activities that aimed to promote integration. Imaging, veterinary practice practicals, and a field trip to a cattle property were classified as the three most valuable learning activities that were designed to promote integration. Veterinary practice practicals, case studies, and palpable anatomy were regarded by students as helping them to learn information presented in other teaching sessions. They also appeared to enhance student motivation, and students indicated that the activities assisted them with their preparation for and performance at examinations. Attitudes to whether the learning exercises helped improve a range of skills and specific knowledge varied, with 39-88% of students agreeing that specific skills and knowledge were enhanced to a large or very large extent by the learning activities. The results indicate that learning activities designed to promote curriculum integration helped improve motivation, reinforced learning, created links between foundational knowledge and its application, and assisted with the development of skills that are related to what students will do in their future careers.

Veterinary student responses to learning activities that enhance confidence and ability in pig handling.

This study examined the use of resource-based learning, consideration of potential troublesome concepts, and knowledge and student evaluation as a method of improving learning outcomes in pig-handling skills for first-year Bachelor of veterinary science students. Learning resources consisted of information and videos provided online, instructors, and animals. Difficulties with regional anatomy, venipuncture technique, fear of pigs, knowledge of their behavior, anesthesia, and dosage calculations were anticipated and steps were taken to minimize these difficulties. Nevertheless, observation and feedback from students indicated that the use of syringes and needles and dosage calculation appeared to be problematic for students. The confidence of students in handling pigs was increased following participation in the class (mean confidence score +/- standard error before and after the class = 4.2 +/- 0.3 vs. 7.4 +/- 0.4, respectively; p < 0.001). Variation in student access to some online resources, and the perceived value of some learning resources and activities, reduced the learning value of some resources and activities. Steps to promote greater student engagement with some of the learning resources and activities may improve learning outcomes in the future. Systematic evaluation of teaching and learning helped illuminate the effectiveness of teaching and identified deficiencies in teaching methods. Consideration of troublesome concepts and knowledge was of value when designing learning activities, selecting learning resources, and suggesting revisions to learning activities.

Curriculum integration within the context of veterinary education.

Curriculum integration has been applied across a range of educational levels as a means of attempting to improve learning outcomes, but there is a paucity of information that has defined and explored curriculum integration as it relates to the teaching of veterinary science. A definition of curriculum integration in the teaching of veterinary science is suggested, which places students as lifelong learners at the center of the educational model. Learning activities are designed to help students see connections among disciplines and topics, thus reinforcing their relevance and helping them to apply their knowledge to different contexts. Curriculum integration at James Cook University in the first three years of the program has been promoted through the design of assessment, the use of case studies, imaging, and palpable anatomy, learning of clinical skills, a research project, animal handling, and a personal professional development program. Advantages and disadvantages of curriculum integration are discussed. Further work is needed to determine if this mode of curriculum design is able to produce veterinary graduates who are better able to meet the challenges of a changing workplace in the twenty-first century.