HDAC4: studying the pro-oncogenic role in human immortalized fibroblasts

In vitro transformation of primary human fibroblasts has been commonly used to understand the specific steps required to generate neoplastic cells following the ordered introduction of cellular and viral oncogenes and/or the down-modulation of tumor suppressor genes. In this thesis I have applied this strategy to explore the pro-oncogenic function of class IIa HDACs. Class IIa histone deacetylases deregulation can contribute to cancer development and progression in different ways. However their real involvement in tumor biology is still debated. To clarify this issue I have investigated the role of HDAC4, a representative member of this class, in human immortalized foreskin fibroblast (BJ/hTERT). I have demonstrated that HDAC4 negatively influences the isolation of clones after retroviral infection. This effect is MEF2-independent and is in part due to the activation of an apoptotic response. Through the generation of BJ/hTERT cells expressing BCL-xL, a Bcl-2 family member characterized by a pro-survival function, it was possible to isolate clones expressing HDAC4 mutated in the 14-3-3 binding sites, suggesting that HDAC4 deregulation can elicit apoptosis. Isolated clones were characterized, and alterations in the cell cycle profile were not observed. However strong repressive forms of HDAC4 were also subject to intense proteolytic degradation. The apoptotic response and the proteasome-mediated degradation were also described using a doxycycline-inducible system. In this case the nuclear resilient mutants of HDAC4 render BJ/hTERT cells more susceptible to apoptosis only when triggered by DNA damage and protein synthesis inhibition, but not by proteasome inhibitors or oxidative stress. In addition all the nuclear resident mutants evidenced a higher rate of proteasomal degradation. Finally, ectopically expressing in BJ/hTERT cells, a form of HDAC4 mutated only in NES sequence (HDAC4-L/A), allowed the isolation of clones characterized by a MEF2-repressed phenotype. This mutation causes the accumulation of the deacetylase in the nuclear compartment, without interfering with 14-3-3 binding. This result suggests a possible implication of these adaptor proteins in the HDAC4 anti-proliferative activity. In parallel murine fibroblast expressing the HDAC4-L/A mutant acquire the ability to growth in an anchorage-independent manner. Overall this thesis sheds some light on the HDAC4 potential of eliciting oncogenic conversion also in human cells managed also by the 14-3-3 bindin

Milk Fatty-Acid Profile after Feeding Increasing Doses of a Mixture of Soybean and Linseed Oils to Pasture Dairy Cows

The goal was to determine the effect of growing intake of a mixture (75:25) of soybean (SoOi) and linseed (LiOi) oils on milk production and composition and milk fatty-acid (MF-A) profile in grazing dairy cows. Twenty-four Holstein cows were assigned to 4 treatments in a completely randomized design with three weeks of adaptation to oil doses and one week of experimental measurements. On a dry matter (DM) basis, cows were fed pasture (63%), energy concentrate (37%) and the SO-LO oil mixture at zero (Tr0%), 2% (Tr2%), 4% (Tr4%) and 6% (Tr6%) of total DM intake equivalent to 0, 0.36, 0.72 and 1.08 kg/cow/day of the oil mixture. The oil mixture was manually mixed-up to the concentrate (7.04 kg DM cow/day) and supplied by halves during each milking time without refusals. Pasture (P = 0.49) and total DM intakes (P = 0.31) were similar between treatments averaging 11.27 and 18.85 kg DM cow-1 day-1 respectively. Milk output (22.71 kg/cow/day) was not affected (P = 0.46). Milk fat content reduced linearly (P  0.05) from T2% (3.37) but was upper (P < 0.05) in Tr4% (4.41) and Tr6% (4.63) remaining under the recommended value of 5:1. Taken together the results suggest that feeding a blend (75:25; SoOi:LiOi) of SiOi an LiOi oils at 4% of total DM intake to pasture dairy cows maximize the milk RA content with a concomitant decrease in the hypercholesterolemic MF-A of milk maintaining a beneficial for health Ω6/Ω3 ratio with low levels of the detrimental trans-9 C18:1 and trans-10 C18:1

ROLE OF DIHYDROCERAMIDE IN CELL SIGNALING

Sphingolipids are a class of bioactive lipids. Ceramide is the hub molecule of the intricate sphingolipid biosynthetic pathway. It is a bioactive lipid, regulating a number of physiological functions such as apoptosis, cell growth arrest, differentiation, senescence, migration and adhesion. The dihydroceramide is the precursor of ceramide along the de novo biosynthetic pathway. Several groups considered the dihydroceramide an inactive molecule. Recent studies associated dihydroceramide with the induction of cellular processes such as cell cycle arrest and programmed cell death. On the other hand this molecule also showed antiapoptotic properties. The goal of my doctorate project is to demonstrate the dihydroceramide implication in the regulation of a pro-survival cell response to stress. Hence, the human gastric carcinoma HGC-27 cells were treated with resveratrol, a molecule that induces dihydroceramide accumulation. Resveratrol is a polyphenol with well known anti-oxidant and anti-tumoral properties. On the other hand it is a calorie restriction mimetic, thus it activates sirtuins, promoting cell survival. A number of studies demonstrated that resveratrol modulates the biosynthetic de novo pathway of ceramide. Here we demonstrated that resveratrol, similarly to the specific inhibitor XM462, inhibits DEGS-1 desaturase activity, inducing dihydroceramide accumulation. This accumulation results in autophagy induction without affecting cell viability. We also obtained this response treating different cell lines with several drugs or conditions known to induce dihydroceramide accumulation. Although autophagy did not affect cell viability, however it causes a delay in cell proliferation. In fact we demonstrated that dihydroceramide accumulation in HGC-27 cells induces a temporary arrest in G0/G1 phase resulting in the delayed cell cycle phases progression. Moreover, we demonstrated that both autophagy activation and cell cycle arrest are temporally subsequent to the unfolded protein response (UPR) which is due to the dihydroceramide accumulation-mediated ER stress. All these results give an important contribute to the understanding of the metabolic role of sphingolipid mediators and their targeting in the anti-tumoral therapy

Long-Range Planning of the OWASA Water Supply System

The Orange Water and Sewer Authority operates a multiple reservoir system consisting of two primary reservoirs and a third, which is an abandoned portion of a quarry. The authority can increase its long-term water supply by obtaining additional storage capacities at the quarry site or by developing a new source outside the existing water sheds. Mathematical optimization techniques were applied to assist in the long-range planning of the capacity expansion of the reservoir system. Linear programming models were developed to estimate the safe yield of the system under various conditions. Safe yield functions were derived for different system configurations, inflow conditions, and working volumes. Using projections of future demands, the schedulng of required capacity expansions was identified for different planning alternatives. A present value cost comparison of the expansion alternatives was performed. The results indicated that substantial savings would be realized by delaying the development of a new source through the expansion of the quarry reservoir.Master of Science in Environmental Engineerin

Effects of feeding combinations of soybean and linseed oils on productive performance and milk fatty acid profile in grazing dairy cows

Thirty-six grazing dairy cows were used to determine the effect of combinations of soybean (SO), and linseed (LO) oils on milk production, composition and milk fatty acid (FA) profile. Treatments were a basal control diet (56% pasture, 44% concentrate) or the control diet supplemented with oils at 4% of estimated total dry matter (DM) intake. Oils were manually mixed to the concentrate in pure forms (SO100 or LO100) or in blends (%w/w) at SO75 - LO25, SO50 - LO50 and SO25 - LO75. Concentrate and oils were thoroughly consumed. Pasture intake (kg DM/cow·day) was 9.27 in control and decreased (p < 0.05) in SO25 - LO75 (8.09) and LO100 (8.98). Total DM intake (kg/cow·day) in control (16.47) increased (p < 0.05) to 17.04 in SO100 and 17.20 in SO75. Yield of fat corrected milk (4% FCM) averaged 20.73 kg in control resulting higher in SO75 (23.73 kg). Milk fat content (g/100g) in control averaged 3.40 and decreased to 2.79 in SO50-LO50 and to 3.06 in SO25 - LO75 treatments. Milk protein content was not affected and milk protein yield increased in SO100 (11%) and SO75 - LO25 (21%) over Control (0.729 kg/cow·day). Milk basal (Control) content (g/100g FA) of C12:0 (2.58), C14:0 (10.21) and C16:0 (25.69) was reduced (p < 0.05) to 1.64, 6.82 and 19.70 respectively in oil supplemented cows. Basal content of C12:0 to C16:0 averaged 38.48 g/100g FA and decreased (27.4%) after oil intake. Basal trans-10 C18:1 (0.46 g/100g FA) increased (p < 0.01) in SO100 (1.48) and SO50-LO50 (1.80). Basal level (g/100g FA) of vaccenic acid (trans-11 C18:1, VA) averaged 3.49 and increased (135%) after oil intake with maximum values observed in LO100 (8.17) and SO50 - LO50 (9.20). Rumenic acid (cis-9, trans-11 C18:2, RA) level (g/100g FA) in milk from Control cows (1.56) increased (p < 0.05) to 3.03 (SO100), 3.21 (SO75 - LO25), 3.24 (SO50 - LO50), 2.33 (SO25 - LO75) and 2.96 (LO100). Results obtained confirmed a great milk fat plasticity in response to PUFA feeding in grazing dairy cows which constitutes a very effective and easy tool in order to improve the healthy value of milk with a potential benefit to the consumer’s health. A net or conclusive response pattern over parameters that improve the healthy value of milk to soybean and linseed oils and their blends was not clearly detected. Taken together, the results suggest some advantage for the SO75:LO25 blend considering the relative costs of both oils, the positive effects on milk, fat and protein yields, the lower hypercholesterolemic FA content of milk and the increase in VA and RA content while maintaining a healthy n - 6/n - 3 ratio and very low levels of the detrimental trans-9 C18:1 and trans-10 C18:1 FA.Fil: Antonacci, Liliana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Area de Producción Animal; ArgentinaFil: Gagliostro, Gerardo Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Area de Producción Animal; ArgentinaFil: Cano, Adriana Virginia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Area de Producción Animal; ArgentinaFil: Bernal, Claudio Adrián. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biologicas; Argentin

Milk Yield and Composition and Pasture Ruminal Digestion in Grazing Dairy Cows Receiving Three Levels of Energy Concentrate Supplementation

The objective of the experiment was to determine the effect of feeding three levels (T3.5, T7.0 and T10.5) of energy concentrate (3.5, 7.0 and 10.5 kg cow-1 day-1) on total dry matter (DM) and energy intakes, milk yield and composition, nutritional value of milk and rumen pasture neutral detergent fiber (NDF) digestion in grazing dairy cows. Twenty-one multiparous Holstein cows in early lactation (70.2 ± 13 days postpartum) producing 37.1 (±4.7) kg of milk were assigned to a 3 treatments (7 cows/treatment) × 3 periods Latin square design. Parameters of ruminal environment and pasture NDF degradation were obtained using 3 additional cows of the same breed fitted with rumen cannulae. On a wet basis, concentrate was composed by corn grain (68%), soybean meal (22%), wheat bran (8%) and a vitamin-mineral nucleus with monensin. Pasture (Medicago sativa, sp) was used in a rotational grazing system with an herbage allowance of 30 kg DM cow-1 d-1. Yield (kg cow-1 d-1) of fat corrected milk (4% FCM) resulted higher (p < 0.05) in T7.0 (29.0) compared to T3.5 (26.8) but similar to T10.5 (30.2). Milk and protein yields were linearly increased (p < 0.01) by concentrate intake. Milk fat (3.13 g/100g) and total solid contents (11.79 g/100g) did not differ whereas milk protein (p < 0.03) and casein (p < 0.01) levels (g/100g) increased linearly from 3.05 to 3.10 (protein) and from 2.42 to 2.47 (casein). Pasture intake decreased but total DM and energy consumption were enhanced showing addition effects after concentrate feeding. Body weight (BW) loss and plasmatic levels of non esterified fatty acids (NEFA) decreased with concentrate intake. Circulating levels of insulin-like growth factor-I (IGF-I) were higher (p < 0.05) in T10.5 while those of glucose, plasma urea nitrogen, insulin and somatotrophin were not affected. Ruminal pH and acetate concentration resulted lower (p < 0.05) in T10.5 when compared to T3.5. The acetate:propionate ratio decreased (p < 0.01) from 4.25 in T3.5 to 3.08 in T10.5 and ruminal ammonia nitrogen levels tended (p < 0.07) to be lower as concentrate intake increased. Kinetics parameters of NDF degradation remained unchanged. The potential hypercholesterolemic fatty acids (FA) of milk (C12:0 to C16:0.) remained unchanged as concentrate intake increased. Milk content of linolenic acid decreased and the n-6:n-3 ratio increased with concentrate intake from 1.56 (T3.5) to 2.57 (T10.5) remaining below the recommended values for human health (<4:1). Milk content of antioxidant vitamins was not significantly altered even when pasture DM intake fall in T10.5 compared to T3.5. Increased consumption of a starch-rich concentrate up to 40% of DM intake of cows showed additive effects on total DM and energy intakes improving milk yield, milk protein and casein contents without negative effects on milk fat concentration or yield. Pasture fiber digestion and nutritional parameters linked to healthy value of milk fat were not affectedEEA RafaelaFil: Salado, Eloy Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Area de Investigación en Producción Animal; ArgentinaFil: Bretschneider, Gustavo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Agencia De Extensión Rural Necochea; ArgentinaFil: Cuatrin, Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Area de Investigación en Producción Animal; ArgentinaFil: Descalzo, Adriana Maria. INTA-LABINTEX-Centre de Coopération Internationale en Recherche Agronomique pour le Déeveloppement (CIRAD), Déepartement PERSYST, UMR Qualisud; FranciaFil: Gagliostro, Gerardo Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Area de Investigación en Producción Animal; Argentin

Productive Response of Dairy Cows Fed with Different Levels of Totally Mixed Ration and Pasture

Forty multiparous Holstein cows in early lactation (66 ± 19 days) were assigned to one of four treatments that consisted in different ratios of total mixed rations (TMR) and pasture at 100% TMR (T0), 75:25 (T1) 50:50 (T2) and 25:75 (T3) over 9 weeks in autumn-winter. Measures of rumen parameters and digestion were performed on 4 additional Holstein cows in late lactation (287 days postpartum) fitted with permanent ruminal fistulae and producing 22.6 (±5.4) kg milk in a 4 × 4 Latin Square design. In T1 to T3 cows were taken to the grazing plot once they finished the pre-planned TMR intake and pasture was offered at 2 times the expected forage DM intake. Milk was analyzed for chemical composition, milk fatty acid (FA) profile and antioxidant compounds. The cows were individually weighed and body condition score (BCS) was determined. After the morning milking, blood samples were taken every 2 weeks and plasma was analyzed for glucose, urea, non-esterified fatty acids (NEFA), insulin, growth hormone (GH) and insulin-like growth factor (IGF-I). Herbage mass in pre grazing strips of pasture averaged 2540 ± 343 kg DM/ha. As TMR intake increased, production variables increased linearly excepting milk fat (3.88 g/100g) and milk protein (3.43 g/100g) contents that were not affected. Milk yield (kg/cow/d) resulted maximal in T0 (34.2) and linearly decreased (p < 0.01) with pasture intake averaging 32.1 (T1), 28.4 (T2) and 26.8 (T3) as a higher energy intake and a lower energy cost associated with grazing activity. Milk fat output (kg/cow/d) resulted higher in T0 (1.35) and T1 (1.25) compared to T2 (1.10) and T3 (1.04). Milk protein yield (kg/cow/d) was also higher in T0 (1.18) and T1 (1.11) compared to T2 (0.96) and T3 (0.92). Total DM (24.09 kg/cow/d) and energy (41.95 Mcal NEL/cow/d)) intakes resulted maximal in T0 decreasing as pasture replaced TMR without effects on conversion efficiency (1.48 kg milk/kg DM). Plasma concentration of glucose, insulin and IGF-I were not affected but GH and NEFA increased as pasture replaced TMR in T3. Ruminal pH (5.91) and total or VFA proportions did not differ but NH3-N concentration resulted higher in treatments with higher proportion of pasture. Kinetic parameters of DM and NDF digestion from pasture or corn silage were not affected. Milk FA profile and milk antioxidant quality showed unfavorably changes as TMR increased by a decrease in rumenic and linolenic acids and content of antioxidant vitamins, without effect on the atherogenicity index. Results suggested a depressing effect of the pasture on total DM and energy intake probably explained by qualitative deficiencies chemical composition of the forage and/or factors that affect animal behavior that may induce losses in body condition of high yielding dairy cows.EEA RafaelaFil: Salado, Eloy Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Area de Investigación en Producción Animal; ArgentinaFil: Bretschneider, Gustavo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Agencia De Extensión Rural Necochea; ArgentinaFil: Cuatrin, Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Area de Investigación en Producción Animal; ArgentinaFil: Descalzo, Adriana Maria. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Tecnología de Alimentos; ArgentinaFil: Gagliostro, Gerardo Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Area de Investigación en Producción Animal; Argentin

Improving the Quality of Milk Fatty Acid in Dairy Cows Supplemented with Soybean Oil and DHA-Micro Algae in a Confined Production System

The objective was to reduce saturated fatty acids (SFA) and increase conjugated linoleic acid (CLA, cis- 9, trans -11 C18:2), α-linolenic (cis- 9, cis- 12, cis- 15 C18:3) and docosahexaenoic (DHA, C22:6) contents in milk from confined dairy cows in order to promote a healthier option. The work was carried out in a commercial farm (Talar) located in Laguna del Sauce, Maldonado (Uruguay). Twenty four cows were assigned to one of two treatments (12 cows per treatment) over a 6 weeks experimental period. Treatments consisted in a control total mixed ration (C-TMR) without supplementary lipids (L) or the same TMR with the addition of 0.144 kg/cow∙day of algae and 0.72 kg/cow∙day of soybean oil (L-TMR). Chemical composition of the TMR (44.27% DM) averaged 15.94% for crude protein (CP), 38.20% neutral detergent fiber (NDF), 20.36% acid detergent fiber (ADF), 5.56% fat, 5.30% ash and 28.6% nonstructural carbohydrate (NSCH) with 1.81 Mcal/kg of net energy for lactation (NEL). After 39 days of feeding, individual milk samples were collected during three consecutive days. From the total milk collected, 20 ml were immediately used for chemical composition (Milko Scan) and 80 ml for analysis for milk FA profile. From week 3 onwards, milk production (kg/cow∙day) resulted higher (P < 0.001) in L-TMR (36.9) compared to C-TMR (35.2). At week 6 of trial, the difference in milk production averaged 5.14% for L-TMR. Supplementary lipids reduced (P < 0.002) milk fat concentration (g/100g) from 3.36 in C-TMR to 2.40 in L-TMR without effect (P = 0.43) on milk protein content (C-TMR = 3.20; L-TMR = 3.07 g/100g). Milk lactose (C-TMR = 4.86, L-TMR = 4.69 g/100g) and urea nitrogen contents (C-TMR = 21.18, L-TMR = 17.33 g/100g) tended (P < 0.056) to decrease in L-TMR as well as fat corrected milk output (C-TMR = 30.89, L-TMR = 29.49 kg/cow∙day, P < 0.098). Lipid supplementation reduced (−23%) milk content of C12:0 to C16:0 FA averaging 45.19 in C-TMR and 34.74 g/100g in L-TMR (P < 0.001). The atherogenic index (AI) of milk decreased (P < 0.001) from 2.69 in C-TMR to 1.50 in L-TMR (−44.2%). Concentration (g/100g) of elaidic (C18:1 trans -9) (0.23) and C18:1 trans -10 (0.44) FA increased (P < 0.001) in L-TMR milk. Milk vaccenic acid (trans- 11 C18:1, VA) increased from 1.08 in C-TMR to 2.56 g/100g of FA in L-TMR (P < 0.001). Milk CLA content (cis- 9, trans- 11 C18:2) increased (127%) from 0.62 in C-TMR to 1.41 g/100g FA in L-TMR milk. Content of α-linolenic acid resulted 20% higher (P < 0.001) in L-TMR milk (0.35 g/100g FA) compared to C-TMR (0.30 g/100g FA). Milk DHA increased from 0 in C-TMR to 0.14 g/100g FA in L-TMR. The omega-6/-3 ratio in C-TMR milk (9.61) was reduced (P < 0.001) to 6.78 in L-TMR milk. Milk oleic acid (cis -9 C18:1) resulted higher (P < 0.001) in L-TMR (23.65) than in C-TMR (19.75 g/100g FA). The nutritional value of milk fat from confined cows was naturally improved by feeding polyunsaturated FA in the ration, obtaining a reduction of saturated FA and increased levels of healthy FA (CLA, DHA and α-linolenic).Fil: Gagliostro, Gerardo Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Balcarce. Area de Producción Animal; Argentina.Fil: Antonacci, Liliana Elisabet. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Balcarce. Area de Producción Animal; Argentina.Fil: Perez, Carolina Daiana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Rossetti, Luciana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto Tecnología de Alimentos; Argentina.Fil: Carabajal, Augusto. Establecimiento Agroindustrial Talar. Laguna del Sauce. Departamento de Maldonado; Urugua

Improving concentration of healthy fatty acids in milk, cheese and yogurt by adding a blend of soybean and fish oils to the ration of confined dairy cows

Compared to pasture based sistems, milk produced in confined dairy systems is characterized by a high saturated fat (SF) content with a lower concentration of healthy fatty acids (FA) such as vaccenic (VA, trans-11C18:1), conjugated linoleic cid (cis-9, trans-11 C18:2, CLA), α-linolenic (cis-9, cis-12, cis-15C18: 3), eicosapentaenoic (EPA, C20:5) and docosahexaenoic (DHA, C22:6) whose presence in milk and dairy products can be increased by feeding polyunsaturated FA (PUFA). The aim of the study was to determine the differences in milk composition and FA profile between a regular (Reg) milk (Reg-Milk), a Reg-Dambo type cheese (Reg-DCh) and a Reg yogurt (Reg-Yog) with that obtained after including a blend (7:1) of soybean (SO) and fish (FO) oils in the total mixed ration (TMR) of lactating dairy cows. The experiment was carried out at the Talar Farm located at Laguna del Sauce, Maldonado Department, Punta del Este, Uruguay Republic during a period of 30 experimental days using a single production batch of 29 Holstein cows. Within this batch, one group of 8 cows (1.88 ± 0.99 calves) in early lactation (135 ± 19 days postpartum) was selected to individually measure milk yield and composition. During the first 7 days of the experiment, cows were fed a TMR without oil-blend inclusion to obtain the Reg-Milk, Reg-DCh and Reg-Yog. From the 8th day onwards, the oil blend was added to the TMR at 4% DM (1.0 kg oil blend cow−1 day−1) and after 23 days of feeding, the modified (Mod-Milk) was analyzed and collected to elaborate the modified Dambo- type cheese (Mod-DCh) and Mod-yogurt (Mod-Yog). Milk yield was recorded daily in the selected 8 cows and milk composition was determined over two consecutive days prior to the start of blend-oil supply (Reg-Milk) and at the end of oil supplementation (Mod-Milk) on days 29th and 30th. Milk-tank samples of Reg-Mi and Mod-Mi were also collected and analyzed for chemical composition and milk FA profile. Cheese and yogurt were assayed for its FA profile. Differences in milk yield and composition and in the FA profile before and after oil-feeding were stated using the Student T-test for paired observations. Milk production (kg∙cow−1∙day−1) slightly (−6.7%) decreased (P < 0.03) from 36.89 (before) to 34.69 after oil feeding. Milk fat content decreased (P < 0.05) from 3.28 to 3.02 g 100 g−1 g leading to a lower (P < 0.02) yield (kg∙cow−1∙day−1) of fat corrected milk (4%FCM) from 32.83 (before) to 29.63 after oil. Milk protein content (g 100 g−1) increased (P < 0.04) from 2.89 (before) to 3.08 (after) oil feeding (+5.92%) a result confirmed (P < .01) in samples taken from the tank. Milk protein output (1.07 kg∙cow−1∙day−1) (P < 0.96), lactose (P < 0.65) and total solid (P < 0.38) contents were not affected. Concentration of non-fat solids (NFS) tended (P < 0.08) to increase from 8.50 in Reg-Mi, to 8.68 g 100 g−1 in Mod-Mi as it was observed (P < 0.001) in samples taken from the tank (8.78 vs. 9.93 g 100 g−1). Yield of NFS tended (P < 0.07) to decrease from 3.14 to 3.01 kg∙cow−1∙day−1 after oil supply. Content of atherogenic FA (C12:0 to C16:0) was significantly (P < 0.064) reduced (−10.29%) from 44.50 (Reg-Mi) to 39.92 g 100 g−1 (Mod-Mi) with a concomitant decrease (P < 0.10) in the atherogenic index (AI) from 2.45 (Reg-Mi) to 2.03 (Mod-Mi). Concentration (g 100 g−1 FA) of elaidic (trans-9 C18:1) and trans-10 C18:1 FA was low in Reg-Mi (0.22 and 0.34 respectively) but tended (P < 0.11) to increase in Mod-Mi (0.43 and 0.95). Concentration (g 100 g−1 FA) of VA resulted higher (+110%, P < 0.039) in Mod-Mi (2.42) compared to Reg-Mi (1.15). Total CLA content (g 100 g−1 FA) increased (P < 0.036) from 0.66 in Reg-Mi to 1.36 in Mod-Mi (+106%). Levels (g 100 g−1) of α-linolenic were higher (P < 0.004) in Reg-Mi (0.34) compared to Mod-Mi (0.29). The omega-6/omega-3 ratio was not changed (P < 0.13) averaging 5.98 in R-Mi and 7.18 in M-Mi. Oleic acid (cis-9 C18:1) content (g 100 g−1) remained unchanged (P < 0.504) averaging 21.99 in Reg-Mi and 22.86 in Mod-Mi. Composition of FA of the Mod-DCh was highly correlated (R2 = 0.999) with FA profile from its original Mod-Mi. A serving of the M-DCh (30 g) theoretically involved a 12.1% reduction in total fat consumption with 16.9% less in SF intake compared to the Reg-Ch. A serving of the M-DCh could putatively increase total CLA consumption by 72.7% compared to the Reg-DCh. Compared to Reg-Yo, a portion (178 g) of the Mod-Yo could increase (69.4%) total CLA intake. The nutritional value of milk fat was improved by feeding a blend of PUFA oils to confined dairy cows and the consumption of the mofified dairy products obtained could promote a lower intake of the potentially atherogenic saturated FA and some increase in healthy FA ingestion.Fil: Gagliostro, Gerardo Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA), Estación Experimental Balcarce. Area de Producción Animal. Balcarce; Argentina.Fil: Antonacci, Liliana Elisabet. Instituto Nacional de Tecnología Agropecuaria (INTA), Estación Experimental Balcarce. Area de Producción Animal. Balcarce; Argentina.Fil: Perez, Carolina Daiana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Rossetti, Luciana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto Tecnología de Alimentos; Argentina.Fil: Carabajal, Augusto. Establecimiento Agroindustrial Talar. Laguna del Sauce. Departamento de Maldonado; Urugua

Effects of calcium salts of unsaturated fatty acids supplementation on ruminal digestion by grazing dairy cows

The objective of this study was to evaluate the effects of calcium salts of unsaturated fatty acids (Ca-FA) supplementation on rumen digestion by dairy cows grazing high-quality pastures. Three cows with cannulas in the rumen were allocated to three dietary treatments in a 3×3 Latin square design. The cows grazed an alfalfa pasture with a herbage allowance of 30 kg dry matter (DM)/cow. Mean pasture quality was: 23% DM, 71% DM in vitro digestibility, 25% crude protein (CP), and 26% neutral detergent fiber (NDF). The treatments consisted in the supplementation with: T0 (5 kg of ground corn plus 0.4 kg of fishmeal), T1 (similar to T0 plus de addition of 0.8 kg de Ca-FA), and T2 (3.2 kg of ground corn, 0.4 kg of fishmeal, and 0.8 kg of Ca-FA replacing a similar part of the corn on an energy basis). The Ca-FA contained 65% of unsaturated and 31% of saturated FA. Total volatile fatty acids (105 mmoles/L), acetato to propionate ratio (3.0), and ruminal pH (5.8) were not affected by Ca-FA supplementation. Isobutyrate concentration in the rumen was increased in T0 (P&lt;0.01). Parameters of in situ ruminal degradation of DM, NDF, and CP of the pasture were similar among treatments. Neither milk production nor milk composition was affected by the treatments. Overall, the results indicated that unsaturated FA supplementation in the form of Ca-FA avoided negative effects on ruminal pasture digestion, even when ruminal pH was relative low