The effect of dietary copper supplementation on fatty acid profile and oxidative stability of adipose depots in Boer x Spanish goats.

A feeding trial was designed to examine the effects of copper sulfate pentahydrate (CuSO(4).5H(2)O) on the fatty acid composition and oxidative stability in muscle and adipose tissues of Boer x Spanish goat kids. Fifteen (n = 5 per treatment) goats were fed 0, 100, or 200 mg of supplemental Cu per day as copper sulfate for 98 d. The animals were slaughtered, and LM, s.c. adipose from the sternal region, and mesenteric adipose tissues were collected. Total lipids were extracted with chloroform:methanol (2:1), methylated and isolated via GLC from all tissues. The subsequent peaks were then positively identified by mass spectrometry. Thiobarbituric acid-reactive substances were measured also. In s.c. adipose, dietary Cu significantly decreased C14:0 (P = 0.03) and C16:0 (P = 0.01). In muscle, C15:0 (P = 0.03) was linearly increased by Cu. Dietary Cu supplementation did not influence oxidative stability in goat muscle or s.c. adipose. Copper supplementation at 200 mg/d resulted in a significant increase in malondialdehyde in mesenteric adipose (P = 0.01) compared with the 0 or 100 mg/d groups. These results indicate that lipid composition may differ from depot to depot and that depending on the depot, dietary Cu seems to elicit a variable response on the fatty acid composition.

The effects of high levels of supplemental copper on the serum lipid profile, carcass traits, and carcass composition of goat kids.

This experiment was conducted to determine the effect of high levels of supplemental Cu (as (CuSO4).5H2O) on the serum lipid profile and carcass traits of goat kids. Fifteen Boer x Spanish wether goat kids (BW = 21.3 +/- 0.7 kg) were housed in individual pens and were assigned randomly to 1 of 3 treatments. Treatments consisted of 1) control (no additional supplemental Cu), 2) 100 mg of Cu/d, and 3) 200 mg of Cu/d. Copper sulfate was placed in gelatin capsules and inserted into the esophagus via a balling gun before the morning feeding. Animals were fed a high-concentrate (70:30 grain:hay) diet for 112 d. Serum lipid profile was determined on d 14 and 112, and BW was recorded after 4-h withdrawals from feed and water. After 112 d, animals were slaughtered, and carcass traits were measured. The left half of 12 carcasses and 9th to 11th rib sections from the right side of 15 carcasses were dissected into separable soft tissue and bone portions. The soft tissue portion was analyzed for moisture, ether extract, CP, and ash. Average daily feed intake decreased (linear; P = 0.05), and G:F increased (quadratic; P = 0.02) in the 100 mg of Cu/d group. Serum cholesterol and triglycerides did not change (P > 0.10); however, NEFA decreased (linear; P = 0.01) as supplemental Cu increased. No differences were observed (P > 0.10) in HCW, chilled carcass weight, or kidney and pelvic fat; however, 12th rib fat (linear; P = 0.01) and adjusted fat thickness (linear; P = 0.03) decreased as Cu supplementation increased. No differences (P > 0.10) in LM area were observed; however, percentage of boneless closely trimmed retail cuts increased (linear; P = 0.04) as Cu supplementation increased. The moisture (%) of the 9th to 11th rib sections increased (linear; P = 0.03), ether extract (%) decreased (linear; P = 0.02), and CP and ash (%) tended to increase (linear; P = 0.09 and 0.06, respectively) as Cu supplementation increased. Carcass composition measured using the left half of the carcass confirmed the values obtained through the 9th to 11th rib sections. Results of this study indicate that supplemental Cu can alter the serum lipid profile, carcass characteristics, and carcass composition of goat kids.

Impact of EasiFlo cottonseed on feed intake, apparent digestibility, and rate of passage by goats fed a diet containing 45% hay.

EasiFlo cottonseed (ECS), produced by coating whole cottonseed (WCS) with cornstarch to simplify handling and mixing with other ingredients, is marketed commercially. The objective of this trial was to determine its digestibility by small ruminants. Four mature Nubian wether goats, in a 4 x 4 Latin square arrangement of treatments, were fed diets that contained about 45% bermudagrass hay (BGH) plus 0, 15.7, 32.7, or 50.3% ECS, with the ECS replacing corn and soybean meal (2:1 ratio) in the concentrate portion of the diet. Feed intakes and digestibility of components were measured, and passage rate was estimated using ytterbium-marked BGH. Dry matter intake decreased at an increasing rate (P < 0.01) as ECS or fat concentration in the diet increased. Digestibility was linearly depressed (P= 0.003) as ECS replaced corn and soybean meal in the diet, primarily due to depressed (P < 0.05) digestibility of NDF, ADF, and nonfibrous carbohydrates (NFC). In contrast, fat digestibility tended to increase (P = 0.11) linearly and N utilization was increased (P = 0.04) linearly as ECS concentration was increased. Passage kinetics were not altered. Based on regression estimates of TDN for BGH and literature values of TDN for other feed ingredients, the total digestible nutrient content of ECS for mature goats fed a 45% roughage diet was estimated to be 78.0 +/- 9.1%, a value quite similar to that (77.2%) proposed for whole cottonseed for large ruminants by NRC tables. Low digestibility of fiber (under 10% of NDF) and of nonfibrous carbohydrate limits the digestibility of DM and energy from ECS.

Effects of high copper supplements on performance, health, plasma copper and enzymes in goats.

Six growing female Nubian goats (average BW=34.8+/-0.55kg, 7-8 months of age) were randomly assigned to either a basal diet (BD, 10-15ppm Cu/DM), or to medium Cu (MC, BD+50mgCu), or to high Cu (HC, BD+100mgCu) diets for 9 weeks. This level would cause Cu toxicity in sheep, but none occurred in the goats. Therefore, Cu supplementation was then increased to 150 and 300mg per head per day, for the following 14 weeks; to 300 and 600mg per head per day, for the next 8 weeks; and to 600 and 1200mg per head per day, for an additional 4 weeks, in the MC and HC group, respectively. Body weight and vital signs were recorded and blood samples collected at different time intervals. Hematological parameters, plasma Cu, sorbitol dehydrogenase (SDH), glutamic oxaloacetic transaminase (GOT), and gamma-glutamyl transferase (GGT) were determined. At the termination of the study, tissue Cu concentration in different organs was also determined. During first 23 weeks (<300mgCu per day) of the study there were no apparent signs of Cu toxicity. Cu supplementation at 600mg per head per day in young Nubian does, had no effect on respiration rate (RR), heart rate (HR), and decreased (P<0.05) rectal temperature (RT) in the HC group only. Leukocyte counts were positively correlated with Cu supplementation (r=+0.296, P<0.02) and negatively correlated (r=-0.254, P<0.05) with RT in the HC group. Plasma SDH increased (P<0.05) when Cu supplementation was >/=300mg per head per day, thus, SDH may serve as an early indicator of Cu toxicosis in goats. Increases (P<0.05) in GOT were noted when Cu intake was >/=600mg per head per day. Contrary to the results observed for SDH and GOT, feeding goats 50mgCu per day or more, resulted in an increased plasma GGT as compared to BD goats. Levels of SDH, GOT and GGT of the BD goats were within normal range. Plasma Cu was not indicative of Cu status of animals. Copper improved ADG by 28% at the 100-150ppm level in diet. No relationship between Cu intake and hair Cu was found in the present study. Highest concentration of Cu was found in liver, followed by duodenum, rumen and brain. Results of this study indicate that goats are more resistant to Cu toxicity than sheep. This is one of the first reports documenting significant differences in Cu requirements and tolerance between goats and sheep.