Effects of isochronal induced feed restriction during the transition period on mRNA abundance of the hepatic genes related to lipid metabolism in fat-tailed ewes.

The process of fat mobilization during the transition period (TP) requires deep re-orchestration of the energy indices, and understanding its mechanism has generated considerable interest among the TP-related studies. The present study aims to validate the effect of feed restriction and TP on the mRNA abundance of hepatic genes related to fat metabolism in fat-tailed sheep. Twenty pregnant ewes with the age of 40.8 ± 6.2 (mean ± standard error) month were randomly assigned to control (n = 10) or restriction (n = 10), and investigated from week - 5 to 5 relative to parturition. Control animals received 100% DM during the trial. Restriction animals received 100% DM through weeks - 5, - 1, 1 and 5 and were fed with 50, 65, and 80% DM in the weeks - 4, - 3, - 2 and 2, 3, and 4, respectively. On the third week of experiment (65%) during both pre- and post-partum, the hepatic tissue was biopsied, and the mRNA load of the fatty acid synthase, acetyl-CoA carboxylase, carnitine palmitoyltransferase (CPT) 1, CPT2, and acyl-CoA synthase long-chain family member-1 genes was quantified by the TaqMan qPCR technique. Data were analyzed using the mixed model procedure of SAS. The mRNA abundance of the target genes was not influenced by feed restriction, during the pre- and post-partum periods. Parturition suppressed the mRNA abundance of target genes in both groups. It can be concluded that the fat-tailed sheep are well adapted to feed scarcity in the harsh environment and would have a higher capacity for the metabolism of fat mobilization during the negative energy balance.

Prepartum and Postpartum Feed Restrictions Affect Blood Metabolites and Hormones Reducing Colostrum and Milk Yields in Fat-Tailed Dairy Sheep.

This study aimed to investigate the effect of prepartum and postpartum feed restriction on body weight (BW), blood metabolites, and hormones as well as colostrum and milk yields and compositions in fat-tailed dairy sheep. In this study, 20 multiparous and pregnant ewes were randomly allocated to either the control (Ctrl; n = 10) or the feed-restricted (FR; n = 10) groups from week -5 to week 5 relative to parturition. Despite dry matter intake being decreased in the FR group compared to the Ctrl throughout both prepartum and postpartum periods, no differences in BW were detected between groups in any of the studied periods. Feed restriction increased both free fatty acids and beta-hydroxybutyrate concentrations during both prepartum and postpartum periods. Similarly, feed restriction increased triglyceride concentration postpartum. Additionally, feed restriction increased insulin and growth hormone and decreased prolactin concentrations during both prepartum and postpartum periods. Feed restriction caused a decreased colostrum yield and a relative increase of the main colostrum components in the FR group. Similarly, milk yield decreased in the FR group compared to the Ctrl group, although milk components were not affected. In conclusion, feed restriction did not affect BW but decreased colostrum and milk yield in fat-tailed dairy sheep.

Correction to: Camelids: new players in the international animal production context.

In the originally published version of the article, Figure 4 image has an error. Corrected Fig. 4 is shown below.

Acute mechanical stress in primary porcine RPE cells induces angiogenic factor expression and in vitro angiogenesis.

BACKGROUND: Choroidal neovascularization (CNV) is a major cause of blindness in patients with age-related macular degeneration. CNV is characterized by new blood vessel growth and subretinal fluid accumulation, which results in mechanical pressure on retinal pigment epithelial (RPE) cells. The overexpression of RPE-derived angiogenic factors plays an important role in inducing CNV. In this work, we investigated the effect of mechanical stress on the expression of angiogenic factors in porcine RPE cells and determined the impact of conditioned medium on in-vitro angiogenesis. RESULTS: The goal of this study was to determine whether low levels of acute mechanical stress during early CNV can induce the expression of angiogenic factors in RPE cells and accelerate angiogenesis. Using a novel device, acute mechanical stress was applied to primary porcine RPE cells and the resulting changes in the expression of major angiogenic factors, VEGF, ANG2, HIF-1α, IL6, IL8 and TNF-α, were examined using immunocytochemistry, qRT-PCR, and ELISA. An in vitro tube formation assay was used to determine the effect of secreted angiogenic proteins due to mechanical stress on endothelial tube formation by human umbilical vein endothelial cells (HUVECs). Our results showed an increase in the expression of VEGF, ANG2, IL-6 and IL-8 in response to mechanical stress, resulting in increased in vitro angiogenesis. Abnormal epithelial-mesenchymal transition (EMT) in RPE cells is also associated with CNV and further retinal degeneration. Our qRT-PCR results verified an increase in the expression of EMT genes, CDH2, VIM and FN1, in RPE cells. CONCLUSIONS: In conclusion, we showed that acute mechanical stress induces the expression of major angiogenic and EMT factors and promotes in vitro angiogenesis, suggesting that mechanical stress plays a role in promoting aberrant angiogenesis in AMD.

Camelids: new players in the international animal production context.

The Camelidae family comprises the Bactrian camel (Camelus bactrianus), the dromedary camel (Camelus dromedarius), and four species of South American camelids: llama (Lama glama), alpaca (Lama pacos) guanaco (Lama guanicoe), and vicuña (Vicugna vicugna). The main characteristic of these species is their ability to cope with either hard climatic conditions like those found in arid regions (Bactrian and dromedary camels) or high-altitude landscapes like those found in South America (South American camelids). Because of such interesting physiological and adaptive traits, the interest for these animals as livestock species has increased considerably over the last years. In general, the main animal products obtained from these animals are meat, milk, and hair fiber, although they are also used for races and work among other activities. In the near future, climate change will likely decrease agricultural areas for animal production worldwide, particularly in the tropics and subtropics where competition with crops for human consumption is a major problem already. In such conditions, extensive animal production could be limited in some extent to semi-arid rangelands, subjected to periodical draughts and erratic patterns of rainfall, severely affecting conventional livestock production, namely cattle and sheep. In the tropics and subtropics, camelids may become an important protein source for humans. This article aims to review some of the recent literature about the meat, milk, and hair fiber production in the six existing camelid species highlighting their benefits and drawbacks, overall contributing to the development of camelid production in the framework of food security.

Reporting temporal fluctuations of hepatic C16 and C18 fatty acids during late gestation and early lactation in dromedary camel.

Based on current knowledge, C16 and C18 fatty acids (FA) are considered the most functional FA in hepatic metabolism. Although these FAs have been satisfyingly investigated in cattle, other species such as camel have been neglected. For this reason, the current study was designed to scrutinize changing patterns of C16 and C18 FAs in 10 dromedary camels from the last 2 months of gestation to the first months of lactation. Camels were grazed on natural pasture and supplemented with a balanced ration. Liver biopsies were obtained through blind biopsy technique at about 60, 45, 30, and 15-day antepartum (AP), and at 3, 15, 30, 45, and 60 post-partum (PP). Data were analyzed by the ANOVA procedure of SPSS with repeated measurements. From 15-day AP, saturated FA content of the liver declined (P < 0.01) and 15-day PP reached its peak (P = 0.02). At 30-day PP it went down (P < 0.01), and re-elevated at 45-day PP (P < 0.01) but remained at a steady state for the duration of the study. Mono-unsaturated and polyunsaturated FA content of hepatic tissue were constant throughout AP, albeit observed to peak at 15-day AP compared with 45 (P = 0.04) and 30-day AP (P < 0.01) for mono-unsaturated FAs, and with 60-, 45-, and 30-day AP (P ≤ 0.01) for polyunsaturated FAs. The palmitic acid content of the liver reached a nadir at 30-day AP (P < 0.01), increased sharply (P < 0.01) at the next sampling time-point, and had a trend to escalate until 3-day PP. Palmitoleic acid levels were unchanged from 60- to 30-day AP, decreased at 15 AP and 3-day PP, increased at 15-day PP, then remained constant until the end of the study period (P ≤ 0.04). Stearic acid content started to grow at 15-day AP and reached its peak at 15-day PP (P < 0.01). At 30-day PP, stearic level in liver dropped abruptly (P < 0.01), then intensified at 45-day PP and did not change after; hepatic content of stearic acid was lower during AP compared with PP time-points. Other C18 FAs changed significantly during the study period. These results suggest that parturition could have a profound effect on FA composition and other metabolites in camel liver. Further research is required to establish the metabolic mechanism behind these changes.

Temporal changes in milk fatty acid distribution due to feeding different levels of rolled safflower seeds to lactating Holstein cows.

The objective of this experiment was to follow the time-course changes of the milk fatty acids (FA) and particularly conjugated linoleic acid (CLA), n-3, and n-6 FA in response to feeding whole rolled safflower seed (SS). Eighteen cows were blocked by milk production, days in milk, and parity, and randomly assigned to 1 of 3 diets by replacing whole cottonseed with SS. The control diet contained no SS (SS0), whereas the other diets contained 3% of dry matter as SS (SS3) or 6% SS (SS6). The study was conducted for 8 wk. Cows fed SS produced more milk than SS0, with SS3 producing more milk than SS6, but without a change in milk fat yield or milk fat %. Except for C8:0 FA, changes in milk FA were not observed until the third week of SS feeding. The C8:0 began decreasing during wk 1 of SS feeding and continued to decline to wk 8. Short-chain FA (C6:0 to C11:0) and medium-chain FA (C12:0 to C16:1) concentrations decreased in milk when cows were fed SS, whereas long-chain FA (C18:0 and higher) increased after wk 3. The milk long-chain FA increased from wk 3 until wk 5 and then reached a plateau with little difference between SS3 and SS6, whereas the short-chain FA decreased more in milk from cows fed SS6 than SS3. Total CLA increased slightly less than 5× in milk from cows fed SS compared with SS0. Over the same time frame, n-3 FA declined and n-6 FA increased in the milk from cows fed SS, with no difference between SS3 and SS6. This study indicated that SS fed at 3 and 6% of DM had the potential to increase milk production and the CLA in milk, but with a corresponding increase in n-6 FA.

Supraphysiological oxytocin increases the transfer of immunoglobulins and other blood components to milk during lipopolysaccharide- and lipoteichoic acid-induced mastitis in dairy cows.

Bacterial mastitis causes pathogen-dependent changes of the blood-milk barrier, and these changes can influence the differential transfer of blood components to milk. It is well known that gram-negative pathogens such as Escherichia coli can cause a greater activation of the immune system and thus a more comprehensive transfer of blood components including IgG than gram-positive pathogens such as Staphylococcus aureus. Supraphysiological doses of oxytocin (OT) have been shown to increase the permeability of the blood-milk barrier; however, the effect of OT during experimentally induced mastitis has not been investigated. Therefore, the objective of this study was to examine if intravenous administration of OT during lipopolysaccharide (LPS)- or lipoteichoic acid (LTA)-induced mastitis could influence the transfer of blood components to milk. The hypothesis was that OT could induce a greater transfer of blood components during mastitis. Twenty-seven dairy cows were injected via the teat canal with LPS, LTA, or a saline control followed by an intravenous injection of OT 2h following intramammary challenge. Milk samples were collected every half hour and analyzed for somatic cell count (SCC), IgG, lactate dehydrogenase (LDH), and serum albumin (SA). Due to the chosen dosage of LPS and LTA, there was no difference in SCC between quarters challenged with only LPS or LTA. Quarters challenged with LPS and OT had a higher SCC and a greater transfer of IgG, LDH, and SA compared with quarters challenged with only LPS. Quarters challenged with LTA and OT had a greater transfer of IgG, LDH, and SA, whereas the SCC increase did not differ from quarters only treated with LTA. In quarters treated only with OT, SCC, LDH, and SA increased, but no difference was observed in IgG concentration from untreated control quarters. In conclusion, there are pathogen-specific changes in the blood-milk barrier and OT can induce a greater transfer of blood components to milk in both LPS- and LTA-induced mastitis. Oxytocin could have implications for use as a mastitis therapy, as there was an increased transfer of IgG into the milk.

Differential glucocorticoid-induced closure of the blood-milk barrier during lipopolysaccharide- and lipoteichoic acid-induced mastitis in dairy cows.

Bacteria invading the mammary gland can cause pathogen-dependent differences in the permeability of the blood-milk barrier leading to the differential paracellular transfer of blood and milk components. Glucocorticoids such as prednisolone (PRED) are known to increase the integrity of the blood-milk barrier and quickly restore the decreased milk quality associated with mastitis. The objective of this study was to examine the effect of intramammary PRED on the differential permeability of the blood-milk barrier during mastitis induced by lipopolysaccharide (LPS) from Escherichia coli or lipoteichoic acid (LTA) from Staphylococcus aureus. Thirty-one dairy cows, divided into 6 groups, were injected via a teat canal with LPS, LTA, LPS and PRED, LTA and PRED, saline (control), or PRED. Milk and blood samples were collected 0 to 8h after challenge and analyzed for somatic cell count, IgG, serum albumin, and lactate dehydrogenase in milk, or α-lactalbumin in plasma. Somatic cell count was similarly elevated in LPS- and LTA-challenged quarters and was reduced to control quarter levels only in LTA-challenged quarters with PRED administration. Lactate dehydrogenase activity was highly elevated in LPS quarters and only slightly elevated in LTA quarters, but decreased to control quarter levels with PRED administration. For serum albumin and IgG, only LPS quarters showed an elevation in concentration and PRED treatment reduced the concentration to control quarter level. We found no differences in α-lactalbumin concentrations in plasma in PRED-treated cows compared with cows that only received LPS or LTA. In conclusion, the pathogen-specific appearance of blood constituents in milk during mastitis demonstrates a differential activation of the blood-milk barrier that, in turn, can be manipulated by intramammary glucocorticoids. The results show that the administration of PRED during mastitis increases the blood-milk barrier integrity but has implications in reducing the transfer of IgG that specifically occurs during E. coli mastitis. In addition, it can also reduce the number of migrating immune cells dependent on the mastitis-inducing pathogen. Potential effects of PRED on the cure of naturally occurring mastitis have to be taken into consideration.