All animal handling and experimental procedures were conducted in accordance with protocols approved by the Institutional Animal Care and Use Committee (IACUC) of Fort Valley State University (Fort Valley, GA, USA). The study was designed to evaluate the effects of dietary dried distillers grains with solubles (DDGS) incorporated into two forage-based feeding systems on subsequent meat quality characteristics of Spanish meat goats. Thirty-six intact male Spanish goats approximately 5 months of age with an initial body weight of 24 ± 1.8 kg were used. All experimental animals were dewormed and given appropriate vaccination prior to the start of a feeding trial. A 30-d adjustment period was used to adapt goats to the new feeding facilities and allowed goats to recover from stresses associated with weaning. Prior to initiation of the experiment, animals were individually weighed and individually housed in 1.2 m × 1.2 m elevated pens with ad libitum access to water. Goats were then randomly assigned to one of four dietary treatments using a completely randomized design, with each animal serving as an experimental unit.

Animals were fed one of four isonitrogenous (17.1 ± 0.1% crude protein) and isocaloric (3.2 ± 0.09 Mcal/kg dry matter) experimental diets for a period of 60 d. The dietary treatments consisted of: 1) an alfalfa hay-based diet (AL); 2) an alfalfa hay-based diet supplemented with DDGS (ALDS), in which DDGS replaced conventional corn and soybean meal; 3) a sericea lespedeza hay-based diet (SL); and 4) a sericea lespedeza hay-based diet supplemented with DDGS (SLDS), with DDGS similarly replacing corn and soybean meal (Table 1).

Table 1.Ingredient and nutrient composition of alfalfa- and sericea lespedeza-based diets with or without corn dried distillers gain with solubles (DDGS) fed to meat goats.

^aAL = alfalfa hay-based diet; ALDS = AL supplemented with DDGS by replacing corn and soybean meals with DDGS; SL = sericea lespedeza hay-based diet; SLDS = SL supplemented with DDGS by replacing corn and soybean meal with DDGS.

Throughout the feeding period, forage and concentrating portions of each diet were offered ad libitum once daily at 0700 h. Fresh drinking water was continuously available. Feed refusals were collected and weighed every 24 h to estimate voluntary dry matter intake and verify feed consumption among treatments. Formulation of the experimental diets ensured that observed responses could be attributed primarily to forage source and DDGS inclusion rather than differences in dietary protein or energy concentrations.

At the completion of the 60-d feeding trial, goats were transported to the USDA-inspected abattoir located at Fort Valley State University (Fort Valley, GA, USA) and harvested using standard humane slaughter procedures consistent with USDA regulations. Following slaughter, carcasses were chilled at 2˚C for 24 h to allow completion of postmortem glycolysis and stabilization of muscle biochemical characteristics prior to sample collection. Ultimate muscle pH was determined 24 h postmortem between the 12th and 13th ribs using a calibrated portable pH meter (Pakton® Model OKPH1000 N; Fisher Scientific, Pittsburgh, PA, USA) equipped with a penetrating electrode.

Carcasses were subsequently split longitudinally along the vertebral column into left and right sides and fabricated into 2.5-cm-thick loin chops using a commercial band saw. Four loin chops from the right side of each carcass containing the longissimus dorsi muscle were collected, finely ground under liquid nitrogen to minimize lipid oxidation and enzymatic activity, packaged in polyethylene bags (NASCO Inc., Fort Atkinson, WI, USA), and stored at −28˚C until proximate composition and fatty acid analyses were performed. An additional four chops from the right side were designated for determination of myoglobin concentration, metmyoglobin formation, and lipid oxidation. Four corresponding loin chops obtained from the left side of each carcass were reserved for instrumental color evaluation, Warner-Bratzler shear force determination, and cooking loss measurements to ensure consistent sample allocation among analytical procedures.

Surface color of loin chops was evaluated using the Commission Internationale de l’Éclairage (CIE) color system. Prior to measurement, chops were allowed to bloom for 30 min at 4˚C to permit oxygenation of myoglobin and development of a stable meat surface color. Color measurements were obtained using a Minolta Chromameter (Model CR-200, Minolta, Osaka, Japan) calibrated with illuminant D65. Three independent readings were collected from different locations on each chop to account for normal surface variation, and average values were calculated for lightness (L*), redness (a*), and yellowness (b*) before statistical analysis.

Following instrumental color evaluation, loin chops were cooked according to the standardized procedures described by Lee et al. [17]. Samples were heated until reaching an internal endpoint temperature of 71˚C, as monitored using a calibrated thermocouple thermometer. This endpoint temperature is widely used for objective assessment of meat quality characteristics. Cooking loss was calculated as the percentage reduction in sample weight following cooking relative to the initial uncooked weight. After cooling, two cylindrical cores were removed from each chop parallel to the orientation of the muscle fibers. Warner-Bratzler shear force (WBSF) was measured using a TA-XT2 texture analyzer (Texture Technologies Corp., Scarsdale, NY, USA) equipped with a Warner-Bratzler shear attachment. The average shear force obtained from the two cores represented the tenderness value for each chop.

Myoglobin concentration and percentage metmyoglobin (MetMb) formation were determined using 5.0 g ground longissimus dorsi muscle samples according to the procedure described by Krywicki [24]. Absorbance values were measured at 525, 572, and 700 nm using a Shimadzu UV-2401 PC spectrophotometer (Shimadzu Corp., Columbia, MD, USA). Myoglobin concentration (mg/g muscle) and MetMb percentage were subsequently calculated using the equations developed by Krywicki [24].

Lipid oxidation was evaluated using the thiobarbituric acid reactive substances (TBARS) assay following the procedure of Buege and Aust [25]. Briefly, 0.5 g of ground muscle tissue was analyzed, and a standard calibration curve was prepared using 1,1,3,3-tetramethoxypropane. Results were expressed as milligrams of malondialdehyde (MDA) per kilogram of muscle tissue.

Moisture, crude protein, ash, and intramuscular fat contents of longissimus dorsi muscle samples were determined according to the official methods of AOAC [26].

Total lipids were extracted from 3.0 g of muscle tissue using a chloroform:methanol (2:1, v/v) extraction system. Samples were homogenized at 30,000 rpm for three 30-s intervals following the procedure of Lee et al. [27]. Lipid extracts were subsequently saponified and converted to fatty acid methyl esters (FAME) according to the American Oil Chemists’ Society official procedures [28]. Fatty acid methyl esters were analyzed using a TRACE GC Ultra gas chromatograph (Thermo Electron Corp., Austin, TX, USA) equipped with an AS-3000 autosampler and flame ionization detector. Separation was achieved using a 60-m SP-2380 fused silica capillary column (0.25 mm internal diameter; Supelco, Bellefonte, PA, USA). The injector temperature was maintained at 240˚C, while the oven temperature was programmed from 130 to 220 ˚C at a rate of 4˚C /min. Helium served as the carrier gas at a flow rate of 1.6 mL/min using a split ratio of 30:1. Individual fatty acids were identified by comparison of retention times with authenticated standards and quantified according to AOCS recommendations [28].

All experimental data were analyzed using the General Linear Model (GLM) procedure of SAS (Version 9.4; SAS Institute Inc., Cary, NC, USA). The experiment was analyzed as a completely randomized design, with individual goats serving as the experimental unit. Least-squares means were calculated for each response variable, and treatment means were separated using the PDIFF option when the overall F-test indicated significant treatment effects. Statistical significance was declared at P < 0.05, whereas values of 0.05 ≤ P < 0.10 were considered to indicate a statistical tendency.

Dry matter intake (DMI) was not affected by dietary treatment (P > 0.42), averaging 1.08, 1.12, 1.29, and 1.12 ± 0.10 kg/d (SE = 0.10) for goats fed AL, ALDS, SL, and SLDS diets, respectively. Similarly, inclusion of dried distillers grains with solubles (DDGS) in either alfalfa- or sericea lespedeza-based diets did not influence average daily gain (ADG; P > 0.25). Mean ADG values were 107.5, 97.1, 126.8, and 110.4 ± 15.76 g/d for goats fed AL, ALDS, SL, and SLDS diets, respectively. Final body weight ranged from 29.9 to 32.5 ± 1.95 kg and carcass yield ranged from 45.9 to 48.6 ± 1.12%, with no significant differences among dietary treatments (P > 0.13).

Ultimate pH of the longissimus dorsi (LD) muscle ranged from 6.24 to 6.36 ± 0.104 and was not affected by dietary treatment (P > 0.85; Table 2). Similarly, instrumental color measurements (CIE L*, a*, and b*) did not differ among treatments (P > 0.05). Cooking loss and Warner-Bratzler shear force (WBSF) values were also unaffected by dietary treatment (P > 0.05), indicating similar water-holding capacity and tenderness across all dietary groups.

Myoglobin concentration and percentage metmyoglobin formation were not influenced by dietary treatment (P > 0.23 and P > 0.16, respectively). Myoglobin concentrations ranged from 4.41 to 4.57 ± 0.230 mg/g LD muscle. Likewise, thiobarbituric acid reactive substances (TBARS) values did not differ among treatments (P > 0.08), indicating similar levels of lipid oxidation regardless of forage source or DDGS inclusion.

Proximate composition of the LD muscle, including moisture, crude protein, and intramuscular fat content, was not affected by dietary treatment (Table 2). However, ash content was greater (P < 0.05) in goats fed the sericea lespedeza (SL) diet than in those fed the alfalfa (AL) diet, whereas goats receiving DDGS-containing diets exhibited intermediate values.

A total of 25 fatty acids were identified in the intramuscular fat of the longissimus dorsi (LD) muscle from goats receiving the four experimental diets (Table 3). These included eleven saturated fatty acids (SFA; C10:0-C22:0), six monounsaturated fatty acids (MUFA; C14:1n5-C20:1n9), and eight polyunsaturated fatty acids

Table 2.Quality characteristics of loin chops from meat goats (n = 9) fed alfalfa- and sericea lespedeza-based diets with or without corn dried distillers gain with solubles (DDGS).

^aAL = alfalfa hay-based diet; ALDS = AL supplemented with DDGS by replacing corn and soybean meals with DDGS; SL = sericea lespedeza hay-based diet; SLDS = SL supplemented with DDGS by replacing corn and soybean meal with DDGS

^bTBARS = thiobarbituric acid reactive substances calculated as milligrams malondialdehyde per kg of flesh

^cWBSF = Warner-Bratzler shear force values

Within a row, least squares means that do not have a common letter differ (P < 0.05).

Table 3.Proximate and fatty acid composition, weight percent of fatty acid methyl esters, of longissimus dorsi (LD) muscle, intramuscular fat, from meat goats fed alfalfa- and sericea lespedeza-based diets with or without corn dried distillers gain with solubles (DDGS).

^aAL = alfalfa hay-based diet; ALDS = AL supplemented with DDGS by replacing corn and soybean meals with DDGS; SL = sericea lespedeza hay-based diet; SLDS = SL supplemented with DDGS by replacing corn and soybean meal with DDGS

^bSFA = saturated fatty acids, C10:0 to C22:0

^cMUFA = monounsaturated fatty acids, C14:1n5 to C20:1n9

^dPUFA = polyunsaturated fatty acids, C18:2n6 to C22:5n3

^en-3 = n-3 PUFA, C18:3n3, C20:5n3, and C22:5n3.

^fn-6 = n-6 PUFA, C18:2n6, C18:2, CLA, C18:3n6, C20:3n6, and C20:4n6

^g,hWithin a row, least squares means that do not have a common letter differ (P < 0.05).

(PUFA; C18:2n6-C22:5n3). Palmitic (C16:0), stearic (C18:0), oleic (C18:1n9), and linoleic (C18:2n6) acids were the predominant fatty acids, collectively accounting for approximately 81% - 83% of the total fatty acids.

Most saturated and monounsaturated fatty acids were not affected by dietary treatment (P > 0.05). However, dietary inclusion of dried distillers grains with solubles (DDGS) increased (P < 0.01) the proportions of α-linolenic acid (C18:3n3) and eicosenoic acid (C20:1n9). Goats fed the sericea lespedeza diet supplemented with DDGS (SLDS) also exhibited greater (P < 0.01) concentrations of γ-linolenic acid (C18:3n6) than goats receiving the other dietary treatments. The PUFA:SFA ratio ranged from 0.22 to 0.27 among treatments, while the n-6:n-3 fatty acid ratio ranged from 5.57 to 6.02. Neither ratio differed significantly among dietary treatments (Table 3).

The absence of treatment effects on dry matter intake (DMI), average daily gain (ADG), final body weight, and carcass yield indicates that replacing conventional corn and soybean meal with DDGS did not adversely affect growth performance or carcass characteristics of Spanish meat goats. These findings are consistent with previous studies demonstrating that DDGS can partially replace conventional concentrate ingredients without compromising feed intake, growth rate, or carcass yield in small ruminants [9]-[11]. Because all experimental diets were formulated to be isonitrogenous (17.1 ± 0.1% crude protein) and isocaloric (3.2 ± 0.09 Mcal/kg DM), comparable animal performance was anticipated, suggesting that nutrient supply remained adequate regardless of forage source or DDGS inclusion.

Sericea lespedeza has been reported to contain condensed tannins that may reduce voluntary feed intake and animal performance when present at excessive concentrations because of their effects on nutrient digestibility and palatability. However, goats receiving sericea lespedeza-based diets in the present study did not exhibit reductions in feed intake or growth performance, indicating that the concentration and biological activity of condensed tannins under these dietary conditions were insufficient to produce measurable anti-nutritional effects. These observations agree with recent reviews demonstrating that the effects of condensed tannins on intake and growth are highly dependent on tannin concentration, chemical structure, diet composition, and animal adaptation, with beneficial, neutral, or negative responses reported under different feeding conditions [14][29].

Recent investigations have also suggested that DDGS supplementation can modify ruminal microbial populations and fermentation characteristics without necessarily producing measurable changes in feed intake or growth performance [29]. Likewise, condensed tannins may increase the proportion of rumen undegradable protein by reducing ruminal protein degradation [30]. Although these mechanisms could theoretically enhance amino acid availability to the small intestine, no improvements in animal performance were observed in the present study. This likely reflects the fact that dietary protein and energy concentrations were already balanced across treatments, minimizing the potential for additional nutritional benefits from DDGS supplementation or tannin-mediated increases in bypass protein.

Collectively, these results demonstrate that DDGS can successfully replace conventional corn and soybean meal in either alfalfa- or sericea lespedeza-based diets without negatively affecting growth performance or carcass yield. From a practical perspective, these findings support the use of DDGS as a nutritionally adequate and economically attractive alternative feed ingredient for forage-based meat goat production systems, particularly where reducing feed costs and improving sustainability are important production objectives.

Ultimate muscle pH is one of the most important indicators of postmortem muscle metabolism because it influences meat color, water-holding capacity, tenderness, microbial stability, and shelf life. In the present study, dietary supplementation with DDGS or substitution of alfalfa with sericea lespedeza did not alter ultimate pH of the longissimus dorsi muscle. The observed pH values (6.24 - 6.36) are consistent with recent reports describing goat meat as frequently exhibiting an intermediate ultimate pH, which is influenced by preslaughter stress, muscle glycogen reserves, and postmortem glycolysis [31]. In contrast to previous reports in lambs where condensed tannin-containing diets resulted in elevated ultimate pH, possibly because of altered energy metabolism or nutritional stress [32][33], no evidence of impaired postmortem glycolysis was observed in goats receiving sericea lespedeza-based diets. These findings suggest that incorporation of sericea lespedeza and DDGS did not adversely affect muscle energy metabolism prior to slaughter.

Instrumental color is among the most important quality attributes affecting consumer purchasing decisions because it serves as an immediate indicator of freshness and wholesomeness. Meat color is influenced by multiple factors, including myoglobin concentration, pigment oxidation, lipid oxidation, and microbial activity [34][35]. Neither DDGS supplementation nor forage source affected CIE L*, a*, or b* values, indicating that dietary treatments did not alter the visual appearance of fresh chevon. Similar observations have been reported in goats fed DDGS, where modifications in fatty acid composition occurred without significant changes in instrumental color or discoloration during retail display [36]. Likewise, although tannin-containing diets have occasionally produced lighter-colored meat in lambs, possibly because of reduced muscle pigment concentrations [33], no comparable response was detected in the present study. The absence of treatment differences in CIE b* values is also consistent with the similar intramuscular fat concentrations observed among dietary treatments, since yellowness may be influenced by lipid deposition and associated pigments. Collectively, these results indicate that replacing conventional concentrate ingredients with DDGS and incorporating sericea lespedeza into forage-based diets did not compromise the visual quality of goat meat.

Water-holding capacity and tenderness are critical determinants of eating quality and consumer satisfaction. Neither cooking loss nor Warner-Bratzler shear force differed among dietary treatments, indicating that neither forage source nor DDGS supplementation altered muscle structural characteristics associated with moisture retention or tenderness. These findings agree with previous reports in lambs fed condensed tannin-containing diets, where tenderness was similarly unaffected by dietary treatment [33]. Warner-Bratzler shear force values observed in the present study (2.66 - 3.08 kg) fall within the range generally considered acceptable for tender lamb and goat meat [37]. Recent reviews further suggest that tenderness is influenced more strongly by animal age, muscle type, postmortem ageing, and carcass handling than by moderate dietary modifications, particularly when carcass composition remains unchanged [31]. The similar carcass characteristics observed in the present study likely contributed to the absence of dietary effects on tenderness.

Myoglobin concentration and metmyoglobin formation are major determinants of meat color stability during storage and retail display. Myoglobin concentration in the present study was comparable with previously reported values for goat meat [38] and was not influenced by dietary treatment. Likewise, metmyoglobin formation remained unchanged across treatments, indicating that dietary inclusion of DDGS or sericea lespedeza did not alter pigment oxidation. Because the conversion of oxymyoglobin to metmyoglobin contributes directly to surface discoloration [39][40], the absence of differences in these measurements is consistent with the similar instrumental color values observed among treatments.

Lipid oxidation is a major factor affecting flavor deterioration, color stability, and shelf life of meat products. Thiobarbituric acid reactive substances (TBARS) are widely used to estimate the extent of oxidative degradation through quantification of malondialdehyde generated during lipid peroxidation [41][42]. Despite modest increases in selected unsaturated fatty acids associated with DDGS supplementation, lipid oxidation remained unchanged among dietary treatments. Although condensed tannins have frequently been proposed to possess antioxidant properties, their effectiveness depends on tannin concentration, chemical structure, and deposition of phenolic metabolites within muscle tissue. Consequently, measurable reductions in TBARS are not consistently observed. Dahmer et al. [36] similarly reported that goats fed DDGS exhibited increased polyunsaturated fatty acid concentrations without corresponding increases in lipid oxidation or deterioration of meat quality during storage. These findings suggest that the modest enhancement of unsaturated fatty acids associated with DDGS supplementation does not necessarily increase oxidative susceptibility under the conditions evaluated in the present study.

Muscle proximate composition is influenced by numerous factors including genetics, age, sex, nutritional management, and muscle development [43]. In the present study, moisture, crude protein, and intramuscular fat contents were similar among treatments, reflecting the comparable growth performance observed across dietary groups and the formulation of isonitrogenous and isocaloric diets. However, goats receiving the sericea lespedeza diet exhibited greater ash content than those fed the alfalfa diet. This response may reflect alterations in mineral metabolism associated with condensed tannins, which are known to interact with dietary minerals and proteins, thereby influencing ruminal nutrient transformations, mineral availability, and tissue deposition. Recent reviews likewise indicate that condensed tannins can modify nutrient partitioning and mineral utilization, although responses vary depending on tannin concentration and chemical characteristics [29]. Additional research is warranted to determine whether the increased ash concentration observed in goats fed sericea lespedeza reflects differences in mineral intake, ruminal availability, intestinal absorption, or tissue mineral deposition.

Overall, the present findings demonstrate that replacing conventional concentrate ingredients with DDGS in either alfalfa- or sericea lespedeza-based diets maintained the physicochemical quality characteristics of chevon. The absence of adverse effects on pH, color, tenderness, lipid oxidation, and proximate composition indicates that DDGS can be incorporated into forage-based meat goat production systems without compromising fresh meat quality while providing flexibility in feed formulation. This supports the use of DDGS as a sustainable alternative feed ingredient capable of reducing dependence on conventional concentrate sources without negatively affecting consumer-relevant quality attributes.

Fatty acid composition is an important determinant of both the nutritional value and oxidative stability of meat. In ruminants, dietary fatty acids undergo extensive microbial biohydrogenation within the rumen, resulting in relatively high proportions of saturated fatty acids in muscle tissue. Consequently, dietary strategies capable of increasing the deposition of unsaturated fatty acids without negatively affecting meat quality are of considerable interest for improving the nutritional profile of red meat.

In the present study, palmitic (C16:0), stearic (C18:0), oleic (C18:1n9), and linoleic (C18:2n6) acids were the predominant fatty acids in intramuscular fat, together accounting for more than 80% of the total fatty acid content. This distribution agrees with previously reported fatty acid profiles for goat meat and reflects the characteristic lipid metabolism of ruminants. The lack of significant dietary effects on most saturated and monounsaturated fatty acids further suggests that replacement of conventional concentrate ingredients with DDGS did not substantially alter overall lipid metabolism or the major pathways of fatty acid deposition.

In contrast, dietary supplementation with DDGS increased the concentrations of α-linolenic acid (C18:3n3) and eicosenoic acid (C20:1n9), while goats fed the sericea lespedeza diet supplemented with DDGS exhibited greater concentrations of γ-linolenic acid (C18:3n6). These responses are generally consistent with the results of Dahmer et al. [36], who directly evaluated DDGS supplementation in Boer goats and reported that feeding 33% DDGS increased total polyunsaturated fatty acids, including linoleic (C18:2n6), eicosapentaenoic (C20:5n3), and docosapentaenoic (C22:5n3) acids, without adversely affecting meat color or lipid oxidation. Together, these studies indicate that DDGS can modify the concentrations of selected unsaturated fatty acids in chevon while maintaining desirable physicochemical characteristics; however, the magnitude and specific fatty acids affected appear to depend on diet composition and experimental conditions.

Several mechanisms may explain the observed alterations in fatty acid composition. DDGS contain residual corn oil that provides additional unsaturated fatty acids compared with conventional concentrate ingredients. Previous studies in meat goats indicate that DDGS supplementation can influence fatty acid deposition, although effects on ruminal fermentation have not been consistent. Dahmer et al. [36] reported increased concentrations of several polyunsaturated fatty acids in muscle from Boer goats fed DDGS, while Sorensen et al. [23] observed greater polyunsaturated fatty acid concentrations in adipose tissue as DDGS replaced soybean meal in Boer-cross goat diets. In contrast, Ale et al. [44] found that inclusion of up to 30% low-fat DDGS did not significantly affect ruminal acetate, propionate, butyrate, or acetate-to-propionate ratios in Kiko-cross goats. Collectively, these findings suggest that the changes in tissue fatty acid composition associated with DDGS may reflect increased dietary supply and subsequent deposition of unsaturated fatty acids rather than substantial alterations in overall ruminal fermentation. However, because ruminal fatty acid intermediates and biohydrogenation rates were not directly measured in these studies or in the present experiment, the contribution of altered ruminal biohydrogenation remains uncertain.

Condensed tannins present in sericea lespedeza may have further contributed to these responses. Previous studies have demonstrated that condensed tannins can suppress specific ruminal microorganisms involved in biohydrogenation, thereby reducing the conversion of unsaturated fatty acids into saturated fatty acids [45][46]. As a result, greater quantities of dietary polyunsaturated fatty acids may escape ruminal metabolism and become available for absorption and deposition within muscle tissue. Recent meta-analyses likewise indicate that dietary tannins can modify the fatty acid composition of meat in small ruminants, particularly with respect to omega-3 and omega-6 fatty acids, although the magnitude of these responses depends on tannin source, chemical structure, and dietary inclusion level [29].

Although increases in α-linolenic and γ-linolenic acids were observed, the aggregate fatty acid indices, including the PUFA and n-6 ratios, did not differ significantly among dietary treatments. The overall PUFA:SFA ratios remained below the value of approximately 0.45 generally recommended for human diets [47]. Likewise, the n-6:n-3 ratios were slightly above the commonly cited nutritional target of 5:1 or lower. Nevertheless, goat meat is naturally characterized by relatively greater concentrations of polyunsaturated fatty acids than many other red meat species, including appreciable amounts of linoleic, α-linolenic, and arachidonic acids [47]. Therefore, even modest improvements in the concentration of health-promoting unsaturated fatty acids may enhance the nutritional quality of chevon without adversely affecting technological or sensory properties.

The increases in α-linolenic acid observed in both DDGS-containing diets suggest that DDGS itself contributed substantially to the observed changes in fatty acid composition. However, the additional increase in γ-linolenic acid observed in goats receiving the sericea lespedeza-DDGS diet may indicate an interaction between forage type and DDGS supplementation, although the present data do not establish that inhibition of ruminal biohydrogenation was responsible for this response. Because α-linolenic acid also increased in goats fed the alfalfa-DDGS diet, the relative contribution of DDGS supplementation and tannin-mediated inhibition of biohydrogenation cannot be clearly distinguished from the present experiment. This interpretation is consistent with current understanding that in vivo responses to dietary tannins frequently differ from in vitro observations because of microbial adaptation, variation in tannin chemistry, and interactions among dietary components [48][49].

Overall, the present findings demonstrate that dietary inclusion of DDGS can alter concentrations of selected unsaturated fatty acids in chevon without adversely affecting the overall fatty acid profile or physicochemical quality of the meat. Because aggregate fatty acid ratios were not affected by dietary treatment, these changes should not be interpreted as evidence of a generalized improvement in the nutritional quality of chevon. Rather, the results indicate that DDGS can modify specific components of the fatty acid profile while maintaining product quality. Further research directly measuring ruminal fatty acid intermediates, duodenal fatty acid flow, microbial populations involved in lipid metabolism, and tissue fatty acid deposition would provide greater insight into the mechanisms governing fatty acid deposition and the interactive effects of DDGS and condensed tannins on meat lipid composition.