1. Introduction
Over the past few years, there has been a surge in global milk consumption, primarily driven by the steady growth in the world population. [
1] reported that between 2007 to 2017, the global goat population increased by 21.5%. As of now, Asia is ahead of other regions with the largest goat population, currently accounting for 56% of the world's total. Furthermore, the rise in income and better living standards among people has led to a growing trend of consuming premium goat milk products in place of cow's milk. Small size of milk fat particles, high digestibility and low allergy potential are the main reasons goat milk is a preferred choice for infants [
2].
The fat in goat milk contains a ratio of
n-6 to
n-3 fatty acids (FA) of 5:1, which is similar to the recommended ratio for the prevention of cardiovascular disease in humans [
3]. The potential advantages offered by goat milk products have resulted in an increase in their consumption by humans. Recent development in dairy goat production has focused on enhancing the nutritional value of milk and dairy products, as well as improving the functionality of milk and milk products [
4]. In order to improve the quantity and quality of milk, changes have been made in the goat production diet.
Goat milk produced through traditional dairy farming methods typically contains negligible amounts of conjugated linoleic acid (CLA), with alpha linolenic acid (ALA) and docosahexaenoic acid (DHA) being barely detectable. [
5]. Previous studies have demonstrated that supplementing the diet with linseed oil significantly enhanced the quantity of unsaturated fatty acids (UFA) present in goat and cow milk, with particular emphasis on CLA and ALA [6-8]. However, when linseed oil is added alone in the diet, it undergoes biohydrogenation (BH) by rumen microorganisms, leading to the conversion of most of the ALA and CLA to stearic acid (SA, C18:0). This results in a substantial loss of ALA and CLA and an amplified accumulation of SA in milk.
In an
in vitro study, the replacement of linseed oil with fish oil significantly elevated contents of ALA and DHA in rumen fluid of Saanen goats [
9]. A study on dairy cows by [
10] showed that incorporating a blend of tuna fish oil and linseed oil in the diet simultaneously increased CLA, ALA and DHA in milk. As far as we know, there is no published research assessing the potential impact of a combination of fish oil and linseed oil on milk yield, composition, and fatty acid profile in dairy goats. The main objective of this study was to investigate the impact of supplementing linseed oil either alone or in combination with fish oil on milk production, composition, and fatty acid profiles. We hypothesized that supplementing a combination of linseed oil and fish oil would increase healthy FA in milk with minimal effects on intake and ruminal fermentation.
2. Materials and Methods
The study was performed at Experimental Farm, Can Tho University, Vietnam. All procedures were carried out in compliance with the ethical standards stated in the Helsinki Declaration of 1975, revised in 2000, in addition to following the national laws.
2.1. Animals
Four F3 crossbred lactating Saanen goats (♂Saanen × ♀Bach Thao), mid-lactation, 2nd parity, 1.30±0.28 kg of milk and 36.6±1.65 kg of body weight, were housed in individual wooden cages (1.2 m×0.6 m×1.2 m, L×W×H) and offered daily rations as equal meals at 7:00 and 17:00 h. The animals had free access to water and a mineral block, and had enough space to exercise. Prior to conducting the experiment, goats were fed freely a basal diet for 1 week to determine the maximum feed intake.
2.2. Experimental Design and Diets
The animals were assigned to a 4×4 Latin square, each period consisted of 16 days for adjustment and 5 days for sampling. During the experimental period, all goats were fed a basic diet consisting of 40% fresh Para grass (
Brachiaria mutica) and 60% pelleted concentrate (dry matter basis). Treatments were 1) basic diet without oil inclusion as a control (Ctrl), 2.5% linseed oil (LO
2.5), 2.5% linseed oil and tuna oil (3:2 w:w; LFO
2.5) and 4.16% linseed oil and tuna oil (3:2 w:w; LFO
4.16). The ratio (3:2 w:w) of linseed oil and tuna oil used was 2.5% DM in this study according to the findings of [
9]. Oil blend was added at 4.16% in LFO
4.16 diet such that this diet contained the same amount of linseed oil as the LO
2.5 diet. Concentrate was mixed and pelleted once a week. Oil was mixed daily with concentrate before feeding the animals. They then had
ad libitum access to Para grass. Diets were monitored daily to ensure that the goats consumed exactly the ratios as they were designed. Feed ingredients and chemical composition of the diets are shown in
Table 1.
2.3. Sampling and Measurements
Feed offered and refused were recorded daily for each goat during a 5-d period (d15-d19). Feed samples were dried in a forced-air oven (FD 53, Binder, Germany) at 60°C for 72 h. After this, the samples were stored at −20°C until analyses of chemical composition.
The dairy goats were milked daily at 7:30 and 17:30 h and milk yields were recorded at each milking. Milk was sampled in 2 consecutive days (d19-d20) to analyze milk composition. To measure milk FA composition, pooled milk samples from 2-day samplings were stored at –20°C until further analysis. To count somatic cells in milk, samples were taken twice (morning and afternoon) at the beginning and the end day of each period.
On d21, rumen fluid samples were collected at 0 and 3 h post morning feeding using a 100-mL syringe and pH was immediately determined using a digital pH meter (HI-5522, Hanna Instruments, Inc., US). The subsample was then filtered through a clean double layer cotton cloth, and the liquid fraction was acidified with 1M H2SO4 (9:1 v/v), centrifuged at 10,000×g for 15 min and stored at −20°C for the analyses of volatile fatty acids (VFA) and NH3-N concentrations.
2.4. Chemical Analysis
Samples were ground through a 1-mm mesh (Cutting Mill SM100, Retsch, Germany) and subjected to proximate analysis. Feed samples were analyzed for dry matter (DM), organic matter (OM), crude protein (CP), crude fiber (CF), ether extract (EE) and Ash using standard methods [
11]. Analyses of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were done using methods of [
12]. Concentration of NH
3-N was analyzed by the micro-Kjeldahl method. Milk composition including total solid, lactose, protein, fat and solid not fat was analyzed with a MilkoScan infrared automatic analyzer (MilkoScan Mars, Foss, Denmark). The milk samples were warmed at 40°C in a shaking incubator (ISS-4075R, Jeiotech, Korea) prior to the analysis of milk composition. Milk samples were kept in Eppendorf at 1°C and immediately analyzed for somatic cell counts using a milk somatic cell analyzer (Adam-SCC, Nano Entek Inc, Korea).
Concentrations of individual VFA were analyzed using a Thermo Trace 1310 GC system (Thermo Scientific, Waltham, MA, USA) equipped with a flame ionization detector. Aliquots (1 μL) were injected with a split ratio of 10:1 into a 30 m × 0.25 mm × 0.25 μm Nukol fused-silica capillary column (Cat. No: 24107, Supelco, Sigma-Aldrich, St. Louis, MO, USA) with helium carrier gas set to a flow rate of 1 mL/min. Temperature program of the GC was set up following the method of [
13]. Individual VFA peaks were identified based on their retention times, compared with external standards including acetic, propionic, butyric, valeric, iso-butyric and iso-valeric acids (Sigma-Aldrich, USA).
Lipids in feed samples (1 g) were extracted in chloroform:methanol solution (2:1 v:v) following the traditional Folch procedure [
14], with minor modifications as described by [
15]. Lipid content in milk samples (2 mL) were extracted with 25% ammonium solution, 95% ethanol, diethyl ether and petroleum ether, according to the method of Chouinard et al. (1997). One milliliter of internal standard (1 mg C13:0/mL chloroform) was added to all extracted lipids and evaporated to complete dryness under a N
2 stream. Dried lipids of feed and milk samples were then methylated with 3 mL of NaOH in methanol (0.5 M) followed by 2 mL of acetyl chloride in methanol (1:5 vol/vol). The FA methyl esters (FAME) were extracted twice with 2 mL of hexane and pooled extracts were evaporated under a N
2 stream until dryness. The residue was dissolved in 1 mL of hexane and analyzed using a gas chromatograph (Thermo Scientific Trace 1310 GC system, Waltham, MA) equipped with a flame ionization detector. Aliquots (1 μL) were injected at a split ratio of 50:1 into a 100 m × 0.25 mm × 0.25 μm high polar fused silica capillary column (Cat. No: 24056, Supelco Inc., Bellefonte, PA) with helium carrier gas set to a flow rate of 1 mL/min. Temperature program of the GC was set up following the method of [
16]. Individual FAME were identified by comparison of retention times with 37 component FAME mix of standard (Cat. No: CRM47885, Supelco Inc, Bellefonte, PA), CLA mix of standard (Cat. No: O5632, Sigma–Aldrich, Louis, MO), and C18:1
t11 standard (Cat. No: CRM46905, Supelco Inc, Bellefonte, PA).
2.5. Calculations
Metabolizable energy intake (ME) was caculated following the equation of [
17]. Atherogenicity index = [12:0+4(14:0)+16:0]/[MUFA+PUFA] and thrombogenicity index = (14:0+16:0+18:0)/[(MUFA+
n-6 PUFA)/2+3(
n-3 PUFA)+(
n-3 PUFA/
n-6 PUFA)] [
18].
2.6. Statistical Analysis
Data were analyzed using GLM in trình SAS OnDemand for Academics 2021 (SAS Institute Inc., Cary, NC, USA) for a completely randomized design with the statistical model Yij = µ + Di + εij, where Yij = the dependent variable, μ = the overall mean, Di = the effect of diet, and εij = the random residual error. Significant differences among treatment means were compared using Tukey. Statistical tests were performed using SAS OnDemand for Academics 2021 (SAS Institute Inc., Cary, NC, USA). A significant effect of treatment was declared at P < 0.05 and tendencies were declared at 0.05 ≤ P < 0.10.
3. Results
3.1. Intake
Diet had no effect on the intake of DM, CP and ME (
Table 3). Except for C12:0, C16:0, C18:0 and C18:2
c9,
c12, the inclusion of oil resulted in an increased intake of all FA (
Table 3). As expected, compared with other diets, the addition of LO alone or in combination with FO at 4.16% resulted in a greater consumption of C18:3
n-3 (21.2 g/d and 23.4 g/d;
P < 0.05), which is the predominant FA in linseed oil (4.40-14.6 g/d). Intakes of C20:5
n-3 and C22:6
n-3 were greatest with LFO
4.16 (3.49 g/d and 1.73 g/d) compared with LFO
2.5 (1.88 g/d and 0.93 g/d) and other diets (undetected). The total FA intake with LFO
4.16 was 2.52 and 1.42 times greater (
P < 0.05) than those in the Ctrl and other diets with added oil, respectively.
3.2. Milk Yield and Composition
Milk yield of the experimental goats ranged from 1.34 to 1.44 kg/day and did not differ among the diets (
P > 0.05;
Table 4). The milk composition and somatic cell count remained unchanged (
P > 0.05) regardless of the different source and levels of oil inclusion in the diet.
3.3. Ruminal Fermentation Patterns
The diets did not affect ruminal fermentation patterns such as pH, NH
3-N and total VFA (
P > 0.05;
Table 5). Total VFA concentration was higher at 3 h post feeding (59.8-69.1 mM) compared with before feeding (53.1-57.8 mM). Compared with the Ctrl goats fed the basal diet without oil inclusion, there was no change in percentage of individual VFA in goats that were fed 4.16% oil (
P > 0.05;
Table 5).
3.4. Milk Fatty Acids
Supplementation of oils altered the proportions of some medium- and long-chain SFA in milk, including C10:0, C11:0, C12:0 and C14:0 (
Table 6). Compared with the Ctrl group, goats fed LFO
4.16 had the lowest proportions (
P < 0.05) of C10:0 and C11:0 (5.75% and 0.14%, respectively) (9.30% and 0.24%, respectively). Compared with Ctrl (4.45% and 15.2%), the inclusion of oils at 2.5% led to a lower proportion of C12:0 (3.16-3.18%) and C14:0 (11.0-11.4%), but a greater proportion of these FA in LFO
4.16 (2.25% and 8.59%) (
P < 0.001). As expected, the proportions of beneficial FA including C18:1
t11, C18:1
c9,
c9,
t11 CLA and C22:6
n-3 were remarkably increased (
P < 0.05;
Table 6) in goats receiving LFO
4.16. Supplementing the combination of LO and FO at 4.16% resulted in a 589% and 303% increase in C18:1
t11 compared with the Ctrl and SO added alone, respectively. Milk
c9,
t11 CLA was impressively increased with the LFO
4.16 diet,
, accounting for 4.53 and 2.94 times greater concentrations than those in the Ctrl and LO
2.5 diets
, respectively (
P < 0.01). Animals fed LFO
2.5 and LFO
4.16 diets had greater levels of C22:6
n-3 (0.63% and 0.87%;
P < 0.001) compared with those fed the Ctrl and LO
2.5 diets (0.06% and 0.08%).
Feeding LO alone or in combination with FO at 4.16% markedly increased (
P < 0.01;
Table 7) the proportion of C18 UFA compared with other diets. Feeding LO
2.5 and LFO
4.16 reduced SFA and increased UFA, especially MUFA, in milk fat (
P < 0.01;
Table 7). As expected, PUFA was highest in LFO
4.16 (6.39%) compared with the lower values (2.64% and 3.70%) detected in the Ctrl and LO
2.5 (
P < 0.05). Additionally, percentage of total CLA increased (
P < 0.01) from 0.54% and 0.81% with the Ctrl and LO
2.5 diets to 2.43% in the LFO
4.16. Goats fed LFO
4.16 diet exhibited a tendency to increase MUFA/SFA (
P = 0.062) and increased PUFA/SFA (
P < 0.05) in comparison with those fed the Ctrl diet. As the result of decreased proportion of SFA and increased proportions of MUFA and PUFA with the LFO
4.16 diet, atherogenicity and thrombogenicity indices in milk fat decreased by 2.09- and 1.69-fold (
P < 0.05;
Table 7) relative to the Ctrl diet.
4. Discussion
4.1. Intake
The lack of effect of oil supplementation on total DM intake in the current study supports some previous studies in which dairy goats were fed diets containing 3% DM linseed oil [
7] and 2.5% soybean oil [
19]. In a recent study conducted with dairy cows, [
6] detected a decreased tendency in total intake when animals were fed a 3% mixture of linseed, sunflower, and tuna oil. [
20] reported that inclusion of either 2.2% FO or 5.3% sunflower oil in the diet had no effect on total DM intake in dairy goats, but decreased total DM intake in dairy cows. This finding revealed that dairy goats have a lower sensitivity towards intake in the presence of oils added to the diet. [
21] recommended limiting total fat intake in the diet to 6-7% DM, as higher concentrations may result in a decrease in DM intake. In the present study, the highest concentration of EE in the diets was 6.56%
4.2. Milk Yield and Composition
The goats used in this research had a relatively low body weight and a moderate milk production, which could be attributed to the tropical conditions they were managed in. As the air temperature, temperature-humidity index, and rectal temperature rise above critical thresholds, a decline in DM intake and a decrease in milk yield occur in tropical ruminants. Additionally, this can lead to a reduction in the efficiency of milk yield [
22].
There have been inconsistent results in ruminants fed oil supplements. Milk fat depression (MFD) was found when oils were supplemented in cows [
6,
23,
24], but milk fat content remained unchanged when cows were fed 4% linseed oil [
25,
26] and goats fed a 2.5% oil blend [
19]. The negative impact of adding oil to the diet of dairy ruminants, which leads to a reduction in milk fat content, is more commonly detected when the lipid sources used are high in polyunsaturated fatty acids (PUFA).
In most of the experimental conditions that have been studied, MFD is partially linked to a change in ruminal biohydrogenation. This leads to the production of various ruminal intermediates such as
t10 18:1 and
t10,
c12 CLA, which may adversely affect the mRNA abundance of lipogenic enzymes [
27]. When dairy cows were fed milk fat-depressing diets, it resulted in the inhibition of mRNA abundance of mammary lipogenic enzymes. Additionally, supraphysiological concentrations of
t10,
c12 CLA were originally associated with MFD [
28]. In the current study, the milk fat content remained unchanged despite the detection of a higher concentrations of
t10,
c12 CLA in the LFO
4.16 diet. It is worth noting that goats are less responsive to fat supplements compared with cows [
29], which may explain the lack of differences in milk composition observed in this study.
Milk somatic cell counts for goats in this study fluctuated within the standard range for goat milk, which is 1,000 × 10
3/mL [
30], ranging from 658 to 1,032 × 10
3/mL at the beginning and 435-1,046 × 10
3/mL at the end of experiment. The LFO
4.16 diet had an opposite effect on milk somatic cell counts compared to other diets as it showed an increase in this parameter towards the end of the experiment. It is imperative to consider this aspect while conducting future research involving a larger number of goats.
4.3. Milk Fatty Acid Composition
The reduction in C10:0-C14:0 content (
P < 0.01) was partially attributed to slight alterations in the activity of acetyl-CoA carboxylase and other enzymes that involved in the
de novo synthesis of SFA in the mammary gland [
31]. The reduction in C12:0 and C14:0 concentrations in milk fat from goats supplemented with linseed oil and fish oil could have a favorable impact on human health since the consumption of these FA was reported to have an inverse correlation with the occurrence of heart attacks in humans [
32].
That higher milk
c9,
t11 CLA in goats fed LFO
4.16 was in agreement with the finding of [
33]. Milk that contains higher levels of
c9,
t11 CLA originates from the biohydrogenation of linoleic acid and alpha linolenic acid in the rumen as an intermediate or from endogenous synthesis in the mammary gland from vaccenic acid [
34]. Compared to the results (0.098 g/100 g FA) obtained by [
35], in this study, the goats fed with a diet containing fish oil had a greater DHA content in the milk (0.63-0.87 g/100 g FA), where goats were supplemented with extruded linseed and fish oil. The consumption of dairy products with lower atherogenic index values (e.g., DHA) leads to a decrease in total cholesterol in human plasma [
36].
The current research was designed to include linseed oil and fish oil at 4.16%, resulting in an enhancement of milk concentrations of MUFA and PUFA. These findings align with previous studies [
6,
37]. In this study, inclusion of a high PUFA oil mixture in the diet led to a decrease in atherogenicity index and thrombogenicity index, which can effectively counteract the negative impact of high levels of SFA and
n-6 FA present in milk. A notable decrease in atherogenicity and thrombogenicity indices was also detected when cows were fed 3% linseed oil and fish oil [
10] or 3% of linseed oil, sunflower oil and fish oil [
6].
5. Conclusions
There was no impact on intake, ruminal fermentation patterns, milk yield, and milk composition when linseed oil and fish oil were incorporated at 4.16% in the diet of lactating goats. However, this diet effectively increased the levels of healthy milk fatty acids such as C18:1 t11, c9,t11 CLA, and C22:6n-3. Additionally, it decreased milk total SFA, atherogenicity, and thrombogenicity indexes. Thus, supplementing linseed oil and fish oil at 4.16% in the diet of lactating goats could have a positive impact on human health without any adverse effect on animal performance.
Acknowledgments
This study was financially supported by Ministry of Education and Training, Viet Nam (#B2021-TCT-09).
Author Contributions
Conceptualization, L.P.T. and J.J.L.; methodology, D.T.T.M. and T.T.T.H.; formal analysis, D.T.T.M., T.T.T.H. and L.P.T.; data curation, L.P.T. and J.J.L.; writing—original draft preparation, L.P.T.; writing—review and editing, J.J.L.; supervision, L.P.T. and J.J.L.; project administration, L.P.T. All authors have read and agreed to the published version of the manuscript.
Conflicts of Interest
The authors declare no conflict of interest exist.
Acknowledgments
Authors express special thanks to the facility support by Experimental Farm and Laboratory, Can Tho University, Vietnam.
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Table 1.
Ingredients and chemical compositions of experimental diets.
Table 1.
Ingredients and chemical compositions of experimental diets.
Item |
Diet1
|
Ctrl |
LO2.5
|
LFO2.5
|
LFO4.16
|
Ingredient, % DM |
Soybean meal |
15.2 |
15.7 |
15.6 |
15.9 |
Ground corn |
15.5 |
9.46 |
9.03 |
- |
Rice bran |
6.85 |
11.45 |
12.0 |
20.2 |
Para grass |
60.0 |
58.5 |
58.5 |
57.5 |
NaCl |
0.30 |
0.30 |
0.30 |
0.30 |
2Premix |
0.50 |
0.50 |
0.50 |
0.50 |
CaCO3
|
1.74 |
1.62 |
1.53 |
1.43 |
Linseed oil |
- |
2.50 |
1.50 |
2.50 |
Tuna fish oil |
- |
- |
1.00 |
1.66 |
Chemical composition, % of DM unless otherwise noted |
DM |
45.6 |
46.7 |
46.7 |
47.8 |
Ash |
9.80 |
10.2 |
10.2 |
11.2 |
OM |
90.2 |
89.8 |
89.8 |
88.8 |
CP |
17.9 |
17.9 |
17.9 |
18.3 |
NDF |
46.8 |
50.7 |
50.7 |
50.1 |
ADF |
25.4 |
26.4 |
26.4 |
29.4 |
CF |
23.2 |
23.9 |
23.9 |
25.9 |
NFE |
46.9 |
43.3 |
43.3 |
38.4 |
EE |
2.23 |
4.74 |
4.74 |
6.56 |
ME, Mcal/kg DM |
2.33 |
2.55 |
2.55 |
2.61 |
Table 2.
Fatty acid composition in the diet.
Table 2.
Fatty acid composition in the diet.
Fatty acid (g/100 g FA) |
Feed |
|
Diet1
|
Fish oil |
Linseed oil |
Para grass |
Concentrate |
|
Ctrl |
LO2.5
|
LFO2.5
|
LFO4.16
|
C12:0 |
0.08 |
0.01 |
0.69 |
0.03 |
|
0.43 |
0.42 |
0.42 |
0.42 |
C14:0 |
6.33 |
0.06 |
0.84 |
0.17 |
|
0.57 |
0.55 |
0.63 |
0.70 |
C16:0 |
21.6 |
5.52 |
47.2 |
19.5 |
|
36.1 |
38.3 |
38.3 |
39.1 |
C18:0 |
2.03 |
3.22 |
10.1 |
5.34 |
|
8.20 |
8.04 |
8.67 |
7.54 |
C18:1 c9 |
13.9 |
17.9 |
3.63 |
35.6 |
|
16.4 |
18.7 |
18.1 |
20.2 |
C18:2 c9,c12 |
2.39 |
16.5 |
11.4 |
26.1 |
|
17.3 |
16.6 |
16.3 |
13.9 |
C18:3n-3 |
0.29 |
55.8 |
21.5 |
0.68 |
|
13.2 |
14.2 |
13.7 |
14.1 |
C20:5n-3 |
14.9 |
nd2
|
nd |
nd |
|
nd |
nd |
0.15 |
0.25 |
C22:6n-3 |
7.37 |
nd |
nd |
nd |
|
nd |
nd |
0.07 |
0.12 |
SFA |
45.2 |
9.06 |
62.3 |
37.0 |
|
52.2 |
49.7 |
50.6 |
50.3 |
UFA |
54.8 |
90.9 |
37.7 |
63.0 |
|
47.8 |
50.3 |
49.4 |
49.7 |
MUFA |
29.0 |
18.0 |
4.65 |
36.1 |
|
17.2 |
19.4 |
19.0 |
21.2 |
PUFA |
25.8 |
72.9 |
33 |
26.9 |
|
30.6 |
30.9 |
30.3 |
28.5 |
n-3 PUFA |
22.9 |
56.1 |
21.5 |
0.76 |
|
13.2 |
14.2 |
13.9 |
14.5 |
n-6 PUFA |
2.75 |
16.5 |
11.5 |
26.1 |
|
17.3 |
16.7 |
16.4 |
14.0 |
Table 3.
Intakes in dairy goats fed a basal diet without supplement or added mixture of linseed oil and fish oil.
Table 3.
Intakes in dairy goats fed a basal diet without supplement or added mixture of linseed oil and fish oil.
Item |
Diet1
|
SEM |
P |
Ctrl |
LO2.5
|
LFO2.5
|
LFO4.16
|
Main components |
|
|
|
|
|
|
DM, g/day |
1,635 |
1,517 |
1,514 |
1,414 |
112 |
0.190 |
CP, g/day |
297 |
274 |
274 |
262 |
24,0 |
0.300 |
ME, Mcal/d |
3.89 |
3.94 |
3.94 |
3.73 |
0,31 |
0.768 |
Fatty acidsb, g/d |
|
|
|
|
|
|
C12:0 |
0.14 |
0.14 |
0.14 |
0.14 |
0.01 |
0.896 |
C14:0 |
0.20b
|
0.20b
|
0.99a
|
1.67a
|
0.15 |
0.001 |
C16:0 |
12.7 |
13.5 |
15.5 |
18.2 |
1.24 |
0.074 |
C18:0 |
2.92 |
3.71 |
3.56 |
4.21 |
0.33 |
0.138 |
C18:1 c9 |
6.74b
|
11.8ab
|
11.4ab
|
16.4a
|
1.54 |
0.025 |
C18:2 c9,c12 |
6.68 |
11.3 |
9.6 |
12.8 |
1.26 |
0.059 |
C18:3n-3 |
4.40b
|
21.2ab
|
14.6ab
|
23.4a
|
3.29 |
0.024 |
C20:5n-3 |
n.d. |
n.d. |
1.88b
|
3.49a
|
0.35 |
0.001 |
C22:6n-3 |
n.d. |
n.d. |
0.93b
|
1.73a
|
0.17 |
0.001 |
SFA |
18.7b
|
20.2ab
|
24.7ab
|
30.5a
|
2.16 |
0.030 |
UFA |
18.2b
|
44.8ab
|
40.8ab
|
62.1a
|
6.58 |
0.018 |
MUFA |
7.02b
|
12.1ab
|
13.6ab
|
20.2a
|
1.80 |
0.012 |
PUFA |
11.1b
|
32.7ab
|
27.2ab
|
41.9a
|
4.83 |
0.021 |
n-3 PUFA |
4.42b
|
21.3ab
|
17.5ab
|
28.8a
|
3.59 |
0.016 |
n-6 PUFA |
6.70b
|
11.3ab
|
9.65ab
|
12.9a
|
1.26 |
0.058 |
Total FA |
36.8b
|
65.1ab
|
65.5ab
|
92.7b
|
8.51 |
0.021 |
Table 4.
Milk yield and composition in dairy goats fed a basal diet without supplement or added mixture of linseed oil and fish oil.
Table 4.
Milk yield and composition in dairy goats fed a basal diet without supplement or added mixture of linseed oil and fish oil.
Item |
Diet1
|
SEM |
P |
Ctrl |
LO2.5
|
LFO2.5
|
LFO4.16
|
Milk yield, kg/day |
1.44 |
1.34 |
1.36 |
1.44 |
0.15 |
0.687 |
Milk composition, % |
|
|
|
|
|
|
Fat |
2.78 |
3.18 |
2.83 |
3.03 |
0.57 |
0.743 |
Protein |
3.08 |
3.02 |
3.04 |
2.92 |
0.12 |
0.363 |
Lactose |
4.26 |
4.35 |
4.38 |
4.41 |
0.66 |
0.508 |
Solid not fat |
8.14 |
8.18 |
7.71 |
7.96 |
0.42 |
0.451 |
Total solid |
10.5 |
10.7 |
10.6 |
10.9 |
0.89 |
0.716 |
Somatic cell count, ×103/mL |
|
|
|
|
|
|
Initial |
1,032 |
1,007 |
715 |
658 |
538 |
0.696 |
Final |
692 |
720 |
435 |
1,046 |
357 |
0.221 |
Difference |
-340 |
-287 |
-279 |
388 |
622 |
0.377 |
Table 5.
Ruminal fermentation patterns in dairy goats fed a basal diet without supplement or added mixture of linseed oil and fish oil.
Table 5.
Ruminal fermentation patterns in dairy goats fed a basal diet without supplement or added mixture of linseed oil and fish oil.
Item |
Diet1
|
SEM |
P |
Ctrl |
LO2.5
|
LFO2.5
|
LFO4.16
|
0 h |
|
|
|
|
|
|
pH |
6.80 |
6.90 |
6.88 |
6.81 |
0.10 |
0.490 |
NH3-N, mg/dL |
32.2 |
37.8 |
31.5 |
30.1 |
4.50 |
0.182 |
Total VFA, mM |
54.9 |
57.8 |
53.5 |
53.1 |
4.39 |
0.476 |
Acetate,% |
67.0 |
66.4 |
65.3 |
64.7 |
1.62 |
0.254 |
Probionate, % |
17.7 |
18.8 |
19.3 |
20.1 |
1.57 |
0.286 |
Acetate/propionate |
3.78 |
3.54 |
3.38 |
3.22 |
0.38 |
0.254 |
Iso-butyrate, % |
3.81 |
3.60 |
3.39 |
3.23 |
0.13 |
0.608 |
Butyrate, % |
1.85 |
1.82 |
1.78 |
1.73 |
0.49 |
0.466 |
Iso-valerate, % |
8.59 |
8.26 |
8.80 |
8.73 |
0.17 |
0.734 |
Valerate, % |
2.53 |
2.55 |
2.52 |
2.43 |
0.17 |
0.572 |
3 h |
|
|
|
|
|
|
pH |
6.52 |
6.56 |
6.63 |
6.74 |
0.12 |
0.128 |
NH3-N, mg/dL |
37.1 |
32.6 |
37.8 |
29.4 |
5.35 |
0.190 |
Total VFA, mM |
64.5 |
63.0 |
69.1 |
59.8 |
6.47 |
0.321 |
Acetate,% |
66.7 |
66.4 |
67.1 |
66.0 |
2.66 |
0.941 |
Probionate, % |
19.0 |
19.5 |
19.0 |
19.7 |
1.70 |
0.318 |
Acetate/propionate |
3.50 |
3.40 |
3.53 |
3.34 |
0.71 |
0.953 |
Iso-butyrate, % |
3.62 |
3.49 |
3.62 |
3.36 |
0.13 |
0.585 |
Butyrate, % |
1.60 |
1.62 |
1.58 |
1.70 |
0.52 |
0.916 |
Iso-valerate, % |
8.14 |
8.21 |
8.23 |
8.17 |
0.16 |
0.612 |
Valerate, % |
2.19 |
2.22 |
2.16 |
2.31 |
0.15 |
0.403 |
Table 6.
Milk individual fatty acid composition in dairy goats fed a basal diet without supplement or added mixture of linseed oil and fish oil.
Table 6.
Milk individual fatty acid composition in dairy goats fed a basal diet without supplement or added mixture of linseed oil and fish oil.
Fatty acid (g/100 g FA) |
Diet1
|
SEM |
P |
Ctrl |
LO2.5
|
LFO2.5
|
LFO4.16
|
Saturated FA |
C4:0 |
0.44 |
0.81 |
0.40 |
0.56 |
0.28 |
0.255 |
C6:0 |
1.30 |
1.74 |
1.14 |
1.35 |
0.39 |
0.255 |
C8:0 |
1.69 |
1.93 |
1.39 |
1.43 |
0.45 |
0.371 |
C10:0 |
9.30a
|
7.47ab
|
6.64ab
|
5.75b
|
1.16 |
0.024 |
C11:0 |
0.24a
|
0.21ab
|
0.17ab
|
0.14b
|
0.03 |
0.021 |
C12:0 |
4.45a
|
3.18b
|
3.16b
|
2.25c
|
0.23 |
<0.001 |
C14:0 |
15.2a
|
11.0b
|
11.4b
|
8.59c
|
0.66 |
<0.001 |
C15:0 |
0.99 |
0.96 |
1.08 |
1.07 |
0.32 |
0.499 |
C16:0 |
36.2 |
29.1 |
40.0 |
35.8 |
5.23 |
0.120 |
C17:0 |
0.66 |
0.59 |
0.68 |
0.65 |
0.08 |
0.472 |
C18:0 |
6.49 |
10.2 |
8.52 |
7.94 |
2.73 |
0.366 |
C20:0 |
0.03 |
0.04 |
0.09 |
0.12 |
0.05 |
0.106 |
C21:0 |
0.01 |
0.25 |
0.01 |
0.21 |
0.34 |
0.653 |
C22:0 |
0.03 |
0.04 |
0.09 |
0.12 |
0.05 |
0.105 |
C23:0 |
0.02 |
0.02 |
0.02 |
0.03 |
0.01 |
0.422 |
C24:0 |
0.02 |
0.02 |
0.03 |
0.04 |
0.01 |
0.096 |
Unsaturated FA |
C14:1 |
0.29 |
0.20 |
0.20 |
0.15 |
0.06 |
0.080 |
C15:1 |
0.01 |
0.14 |
0.00 |
0.12 |
0.20 |
0.667 |
C16:1 |
0.65 |
0.56 |
0.60 |
0.69 |
0.13 |
0.525 |
C17:1 |
0.06 |
0.05 |
0.05 |
0.06 |
0.08 |
0.990 |
C18:1 t9 |
0.07 |
0.14 |
0.20 |
1.99 |
1.74 |
0.406 |
C18:1 t11 |
0.82b
|
1.40b
|
2.70ab
|
5.65a
|
1.25 |
0.006 |
C18:1 c9 |
18.4ab
|
26.2a
|
16.8b
|
18.6ab
|
3.79 |
0.047 |
C18:2 t9,t12 |
0.12b
|
0.29ab
|
0.38a
|
0.50a
|
0.10 |
0.008 |
C18:2 c9,c12 |
1.13 |
1.58 |
1.07 |
1.30 |
0.21 |
0.054 |
c9,t11 CLA |
0.51b
|
0.79b
|
1.38ab
|
2.32a
|
0.49 |
0.007 |
c12,c12 CLA |
0.01 |
0.01 |
0.02 |
0.02 |
0.02 |
0.413 |
t10,c12 CLA |
0.02b
|
0.02b
|
0.02b
|
0.09a
|
0.02 |
0.012 |
C18:3n-6
|
0.01 |
0.01 |
0.01 |
0.01 |
0.01 |
0.454 |
C18:3n-3 |
0.68 |
0.78 |
0.80 |
0.91 |
0.25 |
0.644 |
C20:1n-9 |
0.02b
|
0.02b
|
0.06ab
|
0.14a
|
0.04 |
0.021 |
C20:2 |
0.01 |
0.01 |
0.01 |
0.02 |
0.01 |
0.075 |
C20:3n-6 |
0.01 |
0.01 |
0.01 |
0.01 |
0.01 |
0.517 |
C20:3n-3 |
0.01 |
0.01 |
0.01 |
0.03 |
0.01 |
0.090 |
C20:4n-6 |
0.04 |
0.04 |
0.04 |
0.04 |
0.02 |
0.985 |
C20:5n-3 |
0.03 |
0.04 |
0.03 |
0.07 |
0.03 |
0.273 |
C22:1n-9 |
0.01 |
0.01 |
0.01 |
0.03 |
0.01 |
0.090 |
C22:2 |
0.01 |
0.02 |
0.09 |
0.19 |
0.16 |
0.421 |
C22:6n-3 |
0.06b
|
0.08b
|
0.63a
|
0.87a
|
0.07 |
<0.001 |
C24:1n-9 |
0.06 |
0.04 |
0.08 |
0.11 |
0.05 |
0.406 |
Table 7.
Milk fatty acid group composition in dairy goats fed a basal diet without supplement or added mixture of linseed oil and fish oil.
Table 7.
Milk fatty acid group composition in dairy goats fed a basal diet without supplement or added mixture of linseed oil and fish oil.
Fatty acid (g/100 g FA) |
Diet1
|
SEM |
P |
Ctrl |
LO2.5
|
LFO2.5
|
LFO4.16
|
FA groups |
|
|
|
|
|
|
C18 UFA |
21.7b
|
31.2a
|
23.4b
|
31.4a
|
0.94 |
0.001 |
SFA |
77.0a
|
67.6b
|
74.8a
|
66.1b
|
2.25 |
0.001 |
UFA |
23.0b
|
32.4a
|
25.2b
|
33.9a
|
2.25 |
0.001 |
MUFA |
20.4b
|
28.7a
|
20.7b
|
27.5a
|
1.45 |
0.003 |
PUFA |
2.64b
|
3.70b
|
4.48ab
|
6.39a
|
1.31 |
0.032 |
n-3 PUFA |
0.78 |
0.91 |
1.47 |
1.89 |
0.74 |
0.229 |
n-6 PUFA |
1.31 |
1.95 |
1.50 |
1.86 |
0.28 |
0.055 |
Total CLA |
0.54b
|
0.81b
|
1.42ab
|
2.43a
|
0.25 |
0.007 |
Indices |
|
|
|
|
|
|
MUFA/SFA |
1.13 |
1.13 |
1.22 |
1.23 |
0.03 |
0.062 |
PUFA/SFA |
0.03b
|
0.05ab
|
0.06ab
|
0.09a
|
0.01 |
0.027 |
Atherogenecity index |
4.61a
|
2.37b
|
3.59ab
|
2.21b
|
0.72 |
0.010 |
Thrombogenicity index |
4.32a
|
2.74ab
|
3.72ab
|
2.56b
|
0.71 |
0.038 |
|
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