Fatty Acids, Unsaturated

The DGI-2013 was developed to reflect compliance with the 2013 Australian Dietary Guidelines. It is based on the previous Dietary Guideline Index [1 (link)] and was updated with major changes relating to age and sex-based food intake recommendations, changes in terminology, and inclusion of a new component relating to unsaturated fats [7 ]. It was developed for adults and guidelines relating to breastfeeding and food hygiene were not included, as these are not relevant to adult’s dietary intake.
The DGI-2013 is comprised of 13 components (Table 1). Each component is scored out of ten, with zero indicating the guideline was not met and ten indicating the guideline was sufficiently met. The total score ranged from 0 to 130; a higher score indicating greater compliance with dietary guidelines and hence, higher diet quality. The components are separated into two categories (1) those that reflect adequate intake of nutritious foods and (2) those that reflect moderation or limited intake of foods and drink high in saturated fat and/or added sugar, added salt or alcohol and low in fiber, known as discretionary foods. Several components have sub-components in order to capture important food choices described in the ADG [7 ], for example, choosing mostly wholegrain or high fiber cereals, and choosing lean meat. The cut-offs used to obtain the maximum score for components were guided by the age and sex-specific food-based daily recommendations outlined in the ADG [7 ]. For components that assess adequate intake of nutritious foods, a maximum score is awarded if the daily consumption meets or exceeded the recommendations outlined in the ADG [7 ] and a proportionate score was given for those who fall below this, a recommended practice for scoring dietary indices [30 (link),31 (link)]. For components that reflect guidelines for limiting intake, a score of ten was awarded for remaining below the cut-off or zero for exceeding it.
The DGI-2013 contains indicators that reflect adequate intake of nutritious foods from core food groups (vegetable, fruit (not including juice), cereal, dairy and alternatives and meat and alternatives) as well as the food variety within these core groups [1 (link),7 ]. These are retained from the original index with amendments to the scoring criteria according to the revised recommendations. The food variety component was based on the variety of foods consumed within the core food groups using the same method outlined in the original index [1 (link)] and analogous to the Recommended Food Score [13 (link)].
The DGI-2013 also reflect recommendations for moderation or limited intake of discretionary foods. “Discretionary foods” describe energy-dense food and drink that are not essential to nutrition [7 ] and were known as “extra foods” in the previous dietary guidelines. Revisions to the scoring cut-off values were based on the revised food intakes recommendations [7 ].
A new component, moderate unsaturated fat is included in the DGI-2013 to reflect the new guidelines that makes allowances for moderate intake of poly- and mono-unsaturated fat intake. There is good evidence to suggest that replacing dietary saturated fatty acids with unsaturated fatty acids is associated with improved blood lipid profiles and reduced inflammation markers [7 ].

Comparisons between the control, CL, and OA joints were performed with the generalized linear model (GLM) using the IBM SPSS v27 software (IBM, Armonk, NY, USA). As OA can be associated with ageing in the horse [21 (link)], age was used as a covariant in the analysis. The resulting p values were adjusted for multiple hypothesis testing controlling the false discovery rate by using the Benjamini–Hochberg procedure (Table 1; Table S1, S2). The Studentʼ t-test was utilized for comparisons between sample types (SF and EV-enriched pellet). The distribution of genders in the study groups was tested with the Fisher’s exact test, and correlations between FA proportions and age were calculated with the Spearman correlation coefficient (r_s). The p value <0.05 was considered statistically significant. The results are presented as the mean ± SD. The supervised discriminant analysis was performed for the FA data to assess how clearly the sample types and diagnosis groups differed from each another, which individual FAs separated them most clearly, and how well the analysis was able to classify the samples to respective joint groups.Table 1

Original p values from the generalized linear model (GLM) of the synovial fluid (SF) and its extracellular vesicle-enriched pellet (EV) fatty acids (FAs) and the calculated Benjamini–Hochberg (B–H) critical values used to control the false discovery rate

SF FA	p group	SF FA	p group × age	SF B–Hcritical value	EV FA	p group	EV FA	p group × age	EV B–Hcritical value
n-3/n-6 PUFAs	3 × 10–14*	n-3/n-6 PUFAs	3 × 10–12*	0.0005	18:0	0.002	22:0	0.002	0.0006
16:1n-7	7 × 10–11*	16:1n-7	1 × 10–8*	0.0011	22:0	0.003	18:0	0.004	0.0011
17:0i	3 × 10–8*	17:0i	1.5 × 10–7*	0.0016	16:0	0.020	16:1n-7	0.032	0.0017
Prod/prec n-6	0.00008*	Prod/prec n-6	0.0005*	0.0022	∆5-DI n-6	0.040	16:0	0.077	0.0022
18:2n-6	0.0006*	16:0i	0.0024*	0.0027	22:1n-9	0.040	22:1n-9	0.079	0.0028
18:0i	0.001*	18:0i	0.0031*	0.0033	20:4n-6	0.088	18:2n-6	0.097	0.0033
16:0i	0.001*	18:2n-6	0.0037*	0.0038	16:1n-9	0.091	18:3n-3	0.109	0.0039
∆5-DI n-6	0.003*	24:1n-9	0.0039*	0.0043	16:1n-7	0.093	Prod/prec n-3	0.139	0.0044
14:0	0.003*	22:0	0.0047*	0.0049	17:0i	0.108	15:0	0.162	0.0050
n-6 PUFAs	0.004*	∆5-DI n-6	0.010	0.0054	15:0	0.109	16:1n-9	0.187	0.0056
22:0	0.004*	n-6 PUFAs	0.012	0.0060	18:2n-6	0.121	∆5-DI n-6	0.202	0.0061
DMA 18:0	0.005*	DMA 18:0	0.015	0.0065	20:0	0.130	20:0	0.205	0.0067
24:1n-9	0.013	20:3n-6	0.020	0.0071	DMA 18:0	0.132	DBI	0.222	0.0072
∆6-DI n-6	0.019	n-3 PUFAs	0.029	0.0076	18:3n-3	0.133	SFAs	0.284	0.0078
n-3 PUFAs	0.023	14:0	0.029	0.0082	DMAs	0.172	UFAs/SFAs	0.312	0.0083
18:3n-6	0.032	18:3n-6	0.046	0.0087	24:0	0.198	DMAs	0.355	0.0089
20:3n-6	0.033	Prod/prec n-3	0.054	0.0092	Prod/prec n-3	0.199	17:0ai	0.412	0.0094
17:0ai	0.043	22:5n-3	0.054	0.0098	DBI	0.208	20:4n-6	0.437	0.0100

The p values that remained significant after the procedure were obtained by comparing the original p value to the corresponding critical value on the same row. Asterisk indicates comparisons for which the direction of the difference is confidently interpreted at the α/2 level. The SF FAs that originally had p values >0.05 in the GLM were excluded from the table. In the EV fraction, no significant differences remained after the procedure, but a similar number of FAs is shown

ai anteiso-methyl-branch, DBI double bond index, DI desaturation index, DMA dimethyl acetal, i iso-methyl-branch, Prod/prec product/precursor ratio, PUFA polyunsaturated fatty acid, SFA saturated fatty acid, UFA unsaturated fatty acid

Animal fat is primarily stored in fatty tissue, which can be further subdivided into adipose fat, subcutaneous fat, intermuscular fat, and marbling fat. The fat found within the muscles is known as marbling, and it helps produce a favorable texture (Lawrie & Ledward, 2014 ). Depending on the animal’s fat excretion and the preparation method, a given piece of meat may include varying amounts of intermuscular and depot fat. Saturated fatty acids (SFA) are commonly thought to make up the bulk of animal fat, whereas over 50% of the fatty acids in meat are unsaturated (Lawrie & Ledward, 2014 ). Lipids in meat typically comprise less than half saturated fatty acids (beef 50–52%) and as much as 70% unsaturated fatty acids (Valsta, Tapanainen & Männistö, 2005 (link)).
The grinding, cooking, and storing steps in the processing of meat products expose lipids to the air, which causes them to oxidize quickly and irreversibly. Meat and meat products lose their desirable flavor and texture because of rancidity, turn brown, and create hazardous substances including malondialdehyde and cholesterol oxidation products due to lipid oxidation (Choe et al., 2014 (link)). The addition of various fruit and waste extract may help in retarding lipid oxidation and reducing the fat content of the meat products. In one study, to a more significant extent, persimmon peel extracts prevented lipid oxidation of pork patties while they were being refrigerated (Choe, Kim & Kim, 2017 (link)). In another study, inulin from chicory root was able to reduce the fat at a significant level in pork and chicken meatball (Montoya et al., 2022 (link)). Thus incorporation of fruit and vegetable waste and their extract in meat products may help in slowing down lipid oxidation and rancidity.