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Pharmacological levels of dietary copper (150–250 mg/kg) improve growth performance in pigs, but the majority of Cu is excreted in the manure and may contribute to accumulation in the soil. This experiment with 4 levels of dietary Cu supplementation (15, 80, 120, and 160 mg/kg) from weaning to d 56 after weaning was conducted to determine the dose-dependent effects of dietary Cu on growth performance and fecal consistency in pigs. From d 56 to slaughter, all pigs received the same grower and finisher diets supplemented with 15 mg/kg Cu. Each treatment comprised 10 pens with 8 pigs each, mixed males and females, as experimental units. The pigs were housed in a nursery unit until d 40 after weaning and in a grow–finish unit thereafter. Growth performance and fecal consistency were determined in 2-wk intervals until d 56; thereafter, growth performance was monitored between d 56 and slaughter. The Cu supplementation linearly increased ADFI and ADG (P

This study was conducted to determine the influence of level (15-160 mg/kg voer)and period (2-8 weeks) of supply of a Cu-supplement on growth performance and expression of Cu absorption-related genes in different segments of the small intestine of weaned pigs. Dit onderzoek is uitgevoerd om de invloed te bepalen van de hoogte (15-160 mg/kg voer) en duur (2- 8 weken) van gebruik van een kopersupplement in het voer van gespeende biggen op de groeiprestaties, mestconsistentie en expressie van genen gerelateerd aan de koperabsorptie vanuit verschillende segmenten van de dunne darm.

Stearoyl-CoA desaturase (SCD) in the bovine mammary gland introduces a cis-double bond at the ¿9 position in a wide range of fatty acids (FA). Several long-chain polyunsaturated fatty acids (PUFA) inhibit expression of SCD, but information on the effect of short-chain fatty acids on mammary SCD expression is scarce. We used a bovine mammary cell line (MAC-T) to assess the effect of acetic acid (Ac) and ß-hydroxybutyric acid (BHBA) in comparison with the effect of various long-chain fatty acids on the mRNA expression of the lipogenic enzymes SCD, acetyl-CoA carboxylase (ACACA), fatty acid synthase (FASN) and their associated gene regulatory proteins sterol regulatory element binding transcription factor 1 (SREBF1), insulin-induced gene 1 protein (INSIG1) and peroxisome proliferator-activated receptor alpha (PPARA)and peroxisome proliferator-activated receptor delta (PPARD) by quantitative real-time PCR. MAC-T cells were treated for 12 h without FA additions (CON) or with either 5 mM Ac, 5 mM BHBA, a combination of 5 mM Ac + 5 mM BHBA, 100 µM C16:0, 100 µM C18:0, 100 µM C18:1 cis-9, 100 µM C18:1 trans-11, 100 µM C18:2 cis-9,12 or 100 µM C18:3 cis-9,12,15. Compared with control, mRNA expression of SCD1 was increased by Ac (+61%) and reduced by C18:1 cis-9 (-61%), C18:2 cis-9,12 (-84%) and C18:3 cis-9,12,15 (-88%). In contrast to native bovine mammary gland tissue, MAC-T cells did not express SCD5. Expression of ACACA was increased by Ac (+44%) and reduced by C18:2 cis-9,12 (-48%) and C18:3 cis-9,12,15 (-49%). Compared with control, FASN expression was not significantly affected by the treatments. The mRNA level of SREBF1 was not affected by Ac or BHBA, but was reduced by C18:1 cis-9 (-44%), C18:1 trans-11 (-42%), C18:2 cis-9,12 (-62%) and C18:3 cis-9,12,15 (-68%) compared with control. Expression of INSIG1 was downregulated by C18:0 (-37%), C18:1 cis-9 (-63%), C18:1 trans-11 (-53%), C18:2 cis-9,12 (-81%) and C18:3 cis-9,12,15 (-91%). Both PPARA and PPARD expression were not significantly affected by the treatments. Our results show that Ac upregulated mRNA expression of SCD1 and ACACA in MAC-T cells. The opposite effect of the PUFA C18:2 cis-9,12 and C18:3 cis-9,12,15 on the these genes and the failure of Ac to mimic the PUFA-inhibited SREBF1 and INSIG1 mRNA expression, suggest that Ac can stimulate mammary lipogenesis via a transcriptional regulatory mechanism different from PUFA.

Stearoyl-CoA desaturase (SCD) is an important enzyme in the bovine mammary gland, where it inserts a cis-double bond at the ¿9 position in a wide range of fatty acids. Investigating SCD expression in the bovine mammary gland generally requires invasive biopsy to obtain mammary tissue. The aim of this study was to evaluate the use of milk somatic cells as a non-invasive alternative to biopsy for measuring mammary SCD expression in dairy cows. Both milk somatic cells and mammary tissue were collected from 14 Holstein-Friesian cows and used for analysis of SCD expression by real-time PCR. The SCD5 mRNA levels in mammary tissue compared with SCD1 were low, and for several milk somatic cell samples, SCD5 expression was even below the limit of detection. A significant relationship was found between SCD1 expression in milk somatic cells and in mammary tissue. In addition, SCD1 expression in milk somatic cells was significantly related to ¿9-desaturase indices in milk, which are commonly used as an indicator of SCD1 activity within the mammary gland. Our study showed that milk somatic cells can be used as a source of mRNA to study SCD1 expression in dairy cows, offering a non-invasive alternative to mammary tissue samples obtained by biopsy.

A comparative non-ruminant species view of the contribution of the large intestinal metabolism to inaccuracies in nitrogen and amino acid absorption measurements is provided to assess potential implications for the determination of crude protein/amino acid digestibility in adult humans consuming lower digestible protein sources. Most of the amino acids in the hindgut are constituents of the microorganisms and significant microbial metabolism of dietary and endogenous amino acids occurs. Bacterial metabolism of nitrogen-containing compounds leads to a significant disappearance of nitrogen in the large intestine. Literature data show that some 79 % of the nitrogen entering the large intestine of the horse is absorbed. For dogs, sows, and growing pigs these estimates are 49, 34 and 16 %, respectively. The coefficient of gut differentiation of humans compares closely to that of dogs while the coefficient of fermentation in humans is the lowest of all non-ruminant species and closest to that of cats and dogs. Large intestinal digesta transit times of humans compare closest to adult dogs. Significant amino acid metabolism has been shown to occur in the large intestine of the adult dog. Use of the growing pig as an animal model is likely to underestimate the fermentation of amino acids in the human large intestine. Based on the significant degree of fermentation of nitrogen-containing components in the large intestine of several non-ruminant species, it can be expected that determination of amino acid digestibility at a faecal level in humans consuming low quality proteins would not provide accurate estimates of the amino acids absorbed by the intestine.

Extensive biohydrogenation of dietary fatty acids (FA) occurs in the rumen of dairy cattle, giving rise to a high proportion of saturated FA in milk fat. Saturated FA may contribute to increased risks of cardiovascular disease and the metabolic syndrome (Williams, 2000). Saturated FA, as well as several mono-unsaturated FA, can be desaturated by ¿9-desaturase, also known as stearoyl-CoA desaturase (SCD), present in the mammary gland of dairy cows. It is known that nutrition, especially polyunsaturated FA (PUFA), can affect the expression of SCD in rodents (Ntambi, 1999). Although various FA have been identified which can affect mammary SCD expression in dairy cattle, such knowledge is limited compared with rodents. Therefore, the objective of this study was to investigate the effect of dietary FA supplementation of C18:1 cis-9, C18:2 cis-9,12 or C18:3 cis-9,12,15, by feeding rapeseed oil, soybean oil or linseed oil respectively, or its mixture, on SCD expression in the mammary gland of dairy cows.