In the 2019-2020 school year, there are at least 30,000 pregnant students on U.S. university campuses who might need a place to pump or nurse while in school. National policies protect the need for time and space for employed lactators, but there are only suggested protections for space for lactating college students. Many postpartum people, members of the campus community, are falling through the gaps of support by their universities. Some universities have developed policies that require lactation rooms for capital construction projects. The state of the policies themselves and consistency of the application in the built space is poorly understood. Few policies address the larger issue of inclusion for this diverse population. This study investigated the issue of lactation rooms on campuses from three different perspectives or domains of knowledge. The work explored the claims made by universities about postpartum support and lactator inclusion (proclamations); the manifestation of those policies in the lactation space (actions); and the user experiences of lactating on their campus (perceptions). The perspectives provide contrasting views on the adequacy of lactation space in this complex ecosystem and the needs for improving the process of developing new policies, the application in capital construction, and the operation of lactation rooms. Merging the socio-ecological model with the human rights model (Availability, Accessibility, Acceptability, and Quality (AAAQ)), lactation policies on two case study campuses were assessed to evaluate the claims made by universities about inclusion and dignity as represented in the built environment. Using a mixed-methods approach of institutional ethnography, an environmental assessment (merging photovoice and indoor comfort measurements), and narrative interviews with lactators, the study centred the lactation room as a site of place-making to demonstrate the overall impact of the interrelationships and intersection of these three domains of knowledge. The results indicated that design and construction standards on the case study campus have changed over time in response to national policies and other influences. The findings illuminate that the facilities themselves have not changed to meet the contemporary needs of lactating bodies of varied academic intersectionalities. Despite policies focused on improving spaces for lactating people, best practice guidelines for lactation rooms, and many publications describing the barriers that users experience in meeting this basic need, universities are still struggling to include all of the lactating people in developing their physical infrastructure and to create the supporting social infrastructure. To address some of the gaps in the immediate future, universities could include the variety of lactating people when creating web-based messaging for lactation room access. Future needs include developing postpartum provisions for the lactators and clearly communicating what is available to them. Universities should develop additional sessions on postpartum support to include in their diversity, equity, and inclusion (DEI) trainings for supervisors. The dramatic change in abortion policies in the U.S. directly impacts this age population. Therefore, student health tracking systems need to incorporate more questions on birth experiences, postpartum needs, and lactation. Universities are unique ecosystems and the current desire to improve in policy and action. There is now an incredible opportunity to explore multi-tiered approaches to improving the DEI landscape. / Doctor of Philosophy / The policy that governs the provisions for lactation rooms for employed workers only requires an outlet, a flat surface, and a place to sit. There are no national policies that provide for dignity in spaces where people pump milk for their infants. College campuses offer a unique opportunity to assess social and physical infrastructures for lactation support. The research questions centred on the lactation room as a site of meaning making to explore questions of the creation of lactation rooms, the policies that govern postpartum bodies, and the experiences of lactating people on college campuses. Using the lactation room as the site, the research explored the claims made by universities about postpartum support and lactator inclusion (proclamations); the manifestation of those policies in the lactation space (actions); and the user experiences of lactating on their campus (perceptions). Using these specific domains of knowledge as a guide, the mixed-methods explored the institutional proclamations through document analysis and informational interviews with institutional employees; the rooms themselves assessed using photos and indoor comfort metrics; and in-depth interviews with lactators. Two universities were selected as case studies to examine the policies and practices of lactation programming and share the stories of lactating people. Results indicated numerous gaps in the connection between the policies, practices, and the needs of the lactating people in this unique ecosystem. Universities have some considerable work to do in overcoming these gaps, including breaking down silos between people and programs in different parts of the university. More work is needed to identify these lactators and bring them into the conversations about their needs as an act of inclusion. Universities can acknowledge this diverse group in their web-based resources, communications, and policies. Future work is needed to continue to identify and fill the gaps in all three areas of proclamations, actions, and perceptions. Improvements in these areas could promote more dignity in the built environment and increase sensations of belonging amongst lactating people on college campuses.

Four multiparous Holstein cows, averaging 44 days in milk and previously fitted with rumina1 and duodenal cannulae, were utilized in a 4 x 4 Latin square design to evaluate effects of dietary nonfibrous carbohydrate (NFC) and rumen undegradable protein (RUP) on metabolic and lactational parameters. Diets were isonitrogenous (17.4% CP) and structured in a 2 x 2 factorial arrangement with levels of NFC at 41 or 47% of dietary OM and RUP at 27 or 41% of dietary CP with inclusion of corn gluten meal, fish meal, and feather meal to increase dietary RUP. When cows were fed diets containing 47% NFC, intake of DM, OM, NFC, and N increased (P ± .05) while those containing 41 % NFC increased (P±.01) intake of NDF and ADF. Ruminal digestibility coefficients were not affected leading to greater quantities of NFC digested resulting in suppressed pH (P ±.01) and acetate (P ±.05) and increased propionate (P ± .05), Diets containing 27% RUP increased (P ±.01) ruminal ammonia and plasma urea nitrogen (N) with 41 % NFC eliciting higher ammonia N concentrations at each RUP level. Bacterial yields (averaging 220 g/d) were slightly higher when 41% NFC diets were consumed with no dietary effects on efficiency. Flow of ammonia N to the small intestine (SI) increased (P ± .01) with 27% RUP. When compared to 41% NFC, diets containing 47% NFC increased (P ± .05) flow of methionine (38.6 vs. 32.5 g/d). Fifty percent of the essential amino acids entering the SI were of bacterial origin. Diets containing 41% RUP elicited lower total tract digestion of N while enhancing that of hemicellulose. Total tract digestion of NFC and ADF was greater when 41% NFC diets were consumed. Yields of milk (38.7 vs. 37.7 kg/d) and lactose (1.94 vs 1.88 kg/d) increased with 27% RUP. Efficiency of production was increased by both 41% NFC and 27% RUP. Total and whey N in milk increased (P 5 ±.05) while milk urea N decreased (P ± .01) with higher (41%) dietary RUP. Increased (P ± .05) absorption of N (490.4 vs. 461.6 g/d) at the SI occurred with the 47 vs. 41 % NFC diets, respectively, with no effects observed on that retained or excreted in the urine or milk. Although supply of methionine to and the absorption of N from the S1 was greater with the 47% NFC diets, no positive effects were observed on nitrogen balance or milk production. Rather, dietary RUP provided greater promise in that lower dietary RUP increased milk production and efficiency while increased RUP enhanced milk N content. Therefore, economics regarding feed costs as well as price for milk and milk components may largely dictate preferential dietary RUP content. Abbreviation key: ADC = apparent digestion coefficient, CGM corn gluten meal, CRN = carbon hydrogen nitrogen, CHO = carbohydrate, CNCPS = Cornell Net Carbohydrate and Protein System, MUN = milk urea nitrogen, N = nitrogen, NAN = nonammonia N, NANMN = nonammonia nonmicrobial N, NFC = nonfibrous carbohydrate, NPN = nonprotein N, PUN = plasma urea N, RDP = rumen degradable protein, RUP = rumen undegradable protein, SI = small intestine, TDC = true digestion coefficient, 41:27 = 41% NFC and 27% RlUP, 47:27 = 47% NFC and 27% RUP, 41:41 = 41% NFC and 31% RUP, 47:41 = 47% NFC and 41% RUP. / Ph. D.

The initiation of lactation involves an increased flow of Ca into mammary secretions, which leads to responses of serum concentrations of Ca and parathyroid hormone (PTH) that may be influenced by dietary Ca. Eight light mares from Farm A and eight Thoroughbred mares from Farm B were bled and milked 10 d pre-foaling, and eight mares (four from each farm) were bled and milked 5 d post-foaling. Milk Ca was measured by two commercial tests, one for [Ca + Mg] and the other [Ca]. Serum PTH and total Ca were measured in 16 mares, and ionized Ca in four mares. Parturition was induced in all mares with fenoprostalene on Farm A, and in four mares with oxytocin on Farm B; no significant difference was found between induction methods or between induced and spontaneous foaling mares. Dietary Ca was 34% DM on Farm A and .79% on Farm B. Mean serum total Ca concentrations decreased from 12.5 mg/dl to a nadir of 11 mg/dl on d 2 post-partum, and mean PTH increased from 46 pg/ml to a peak of 186 pg/ml on d 2 post-partum. Mean serum PTH concentrations were lower (P = .03) and total Ca concentrations were higher (P = -01) on Farm B in comparison to Farm A, probably reflecting the difference in Ca intake. The nadir in mean ionized Ca and total Ca concentrations was reached on d 2 post-partum, 1 day later than has been observed previously in the dairy cow. Milk Ca concentrations increased from 50 ppm 7 d pre-foaling to 350 ppm on the day of foaling, with no difference between farms. The [Ca + Mg] test reached a critical level of 200 ppm 4.5 d pre-foaling, the [Ca] test 2 d pre-foaling. The [Ca + Mg] and [Ca] tests reached 250 ppm 2.5 and 1 d pre-partum, respectively. In short, serum Ca and PTH concentrations showed periparturient changes which reflected dietary Ca pre-partum. Foaling date was more closely associated with milk [Ca] than with [Ca + Mg] and by a critical level of 250 ppm than by 200 ppm. / Master of Science

<p dir="ltr">Murine, or small rodent, models can provide valuable and translatable insights into human pathophysiology. Specifically, we are looking to combine murine models and high-frequency ultrasound to non-invasively investigate microrobot drug delivery systems, cardiac effects of lactation on the mother during postpartum, and cardiac remodeling due to the combination of pregnancy and hypertension.</p><p dir="ltr">Currently, we are looking at the applications of microrobots within the colon to provide targeted treatment for patients suffering from inflammatory bowel disease (IBD). IBD is an overarching term encompassing chronic inflammation of the digestive tract tissue. The standard treatment of IBD includes oral and injectable treatments depending on disease severity. The drawbacks of these therapeutics are the associated systemic toxicity, non-specific treatment allocation, and degradation of the treatment in proximal portions of the gastrointestinal (GI) system. The goal of this research is to use an external magnetic torque to cause the microrobots to tumble to targeted areas of inflammation and release a drug payload. Retroactive locomotion of these microrobots can avoid degradation in the proximal GI tract. Therefore, these microrobots need a smaller drug payload to provide the same efficacy as traditional treatments.</p><p dir="ltr">The cardiovascular system adapts to meet the growing physiological demands of pregnancy. Although this change has been greatly studied, it is unclear if this change in shape and function returns to prepregnant values during postpartum. Previous research has also shown that lactation affects the mother’s hemodynamics during postpartum, but its impact on cardiac morphology is still not completely understood. To study this further, we longitudinally tracked cardiovascular changes using ultrasound and blood pressure measurements in C57BL6/J mice during pregnancy and postpartum that were either lactating or not.</p><p dir="ltr">Chronic hypertension affects approximately 1 in 20 pregnancies and its prevalence in pregnancies continues to increase. The maternal cardiovascular system goes through dynamic changes during pregnancy to meet the demands of perfusing the gestation, especially during the exponential growth seen later in pregnancy. Studies with female C57BL6/J mice demonstrate comparable cardiovascular changes during pregnancy to those observed in humans. Additionally, a study using rats showed the cardioprotective properties of pregnancy against angiotensin II-induced fibrosis. The objective of this study is to characterize non-invasive cardiac remodeling in a small animal model of hypertensive disorders in pregnancy. We used a combination of ultrasound imaging and noninvasive blood pressure measurements to longitudinally monitor the physiological adaptations that occur during pregnancy with superimposed hypertension.</p>

L’objectif du projet présenté dans ce mémoire de maitrise est d’évaluer l’effet du remplacement de la fléole des prés par la fétuque élevée, offertes en espèce pure ou en mélange avec la luzerne, et de vérifier l’impact de la méthode de conservation de la fétuque élevée, soit en ensilage préfané (35 % de matière sèche, MS) ou demi-sec (55 % de MS), sur les performances des vaches en lactation. Pour ce faire, cinq traitements ont été testés : 1) fléole des prés (70 % de la ration) en ensilage préfané ; 2) fléole des prés (42 % de la ration) + luzerne (28 % de la ration) en ensilages préfanés ; 3) fétuque élevée (70 % de la ration) en ensilage préfané ; 4) fétuque élevée (42 % de la ration) + luzerne (28 % de la ration) en ensilages préfanés ; 5) fétuque élevée (70 % de la ration) en ensilage demi-sec. Quinze vaches Holstein (128 +- 33 JEL) ont été distribuées dans un triple carré latin 5 × 5. Afin de comparer les traitements, les contrastes a priori suivants ont été réalisés : 1) fléole des prés-ensilage préfané vs fétuque élevée-ensilage préfané [(FP et FP + L) vs (FE et FE + L)]; 2) espèces pures-ensilage préfané vs mélanges-ensilage préfané [(FP et FE) vs (FP + L et FE + L)]; 3) interaction entre l’espèce de graminée fourragère et le mélange, pour les traitements à base d’ensilage préfané; et 4) ensilage préfané de fétuque élevée vs ensilage demi-sec de fétuque élevée [FE vs. FE (DS)]. Les contrastes ont été considérés comme significativement différents à des valeurs de P <= 0,05 et une tendance a été considérée quand 0,05 < P < 0,10. Les résultats ont démontré que l’espèce de graminée n’a pas influencé la consommation volontaire de matière sèche, la production laitière, et la teneur en gras du lait. La prise alimentaire et la production laitière ont été supérieures avec les mélanges fourragers, mais la teneur en gras du lait n’a pas été avantagée par ces derniers. La teneur en protéine du lait n’a pas été affectée par l’espèce de graminée pour les traitements à base de mélange fourrager, mais a été supérieure avec la fléole des prés pour les traitements de graminées seules. Les vaches ont consommé davantage de fétuque élevée sous forme d’ensilage préfané comparativement à l’ensilage demi-sec, mais la production laitière et la teneur en gras du lait n’ont pas été affectées par le mode de conservation. En somme, les résultats démontrent que la fétuque élevée est une bonne alternative à la fléole des prés pour les vaches en lactation et confirment les effets bénéfiques des mélanges fourragers dans leur ration.

The objective of this study was to determine whether dietary fat supplementation and level of undegradable intake protein (UIP) could affect daily milk output and composition by influencing nutrient supply to the mammary gland. Three lactating Holstein cows (60, 68, and 74 d postpartum) were used in an incomplete 4 x 4 Latin square design (2 x 2 factorial) and fed diets (15.9% CP and 19.5% ADF) with 0% or 2.5% partially hydrogenated tallow and 33% or 41% UIP. A 5:2.5:1 mixture of dried brewer's grains, corn gluten meal, and blood meal was substituted for soybean meal to raise dietary UIP from 33% to 41% UIP. Despite similar DM intake across treatments, cows produced 9% more milk per day when fed 2.5% supplemental fat, 41% UIP, or the combination of 2.5% fat and 41% UIP when compared to the control diet. Fat supplementation depressed milk protein percentage but not daily milk protein output. Mammary blood flow was estimated using the Fick principle at 6-hr intervals for 24 h. Concentration of individual nutrients in arterial (carotid) and venous (abdominal vein) blood and corresponding blood flows were used to calculate nutrient uptakes by the mammary gland. Calculated carbon uptake was 95 to 101% of output when using estimated carbon content of nutrients, and 100 to 106% when using an elemental analyzer to determine actual carbon output in milk. Uptake of glucose, β-hydroxybutyrate, lactate, pyruvate, acetate, and O₂ were not affected by dietary treatment. Triacylglycerol concentration in arterial blood and uptake of long-chain fatty acids were elevated by fat supplementation, resulting in milk fat with a higher percentage of 18-carbon fatty acids and a lower ratio of saturated to unsaturated fatty acids. Arterial essential and total amino acid (AA) concentrations in plasma and whole blood were elevated when cows were fed 41% versus 33% UIP. However, mammary arteriovenous differences, extraction percentages, and uptakes of most AA were not significantly affected by dietary treatments. Across treatments, peptide AA accounted for ~10% of AA in arterial whole blood but no net uptake of peptide AA by the lactating gland was detected. Results indicated that dietary fat supplementation at two levels of UIP can increase milk production by altering mammary lipid metabolism, thereby improving the efficiency of milk synthesis. However, depression of milk protein percentage in response to dietary fat supplementation was not alleviated by elevating arterial essential and total AA through higher dietary UIP. / Ph. D.

Two feeding trials were conducted involving diets supplemented with soybean meal, dried brewers, and wet brewers grains. The first trial involved 24 first-calf heifers averaging 82 d postpartum. After a 20 d protein depletion period in which a 9.4% CP diet was fed, cows were randomly assigned to a 2 x 3 factorial where pelleted (P) or unpelleted (UP) soybean meal supplemented corn diets to 12.2% (L), 15.4% (M), and 18.1% (H) crude protein. During depletion, milk production, dry matter intake, and yields of milk protein, fat, and solids decreased in the range of 15 to 25%. However, these all increased to pre-depletion levels after 26 d of repletion. Considering repletion response separately resulted in no significant differences between P and UP for milk production and constituents, feed intake, and plasma urea. However, using depletion to covariably adjust means resulted in P diets favoring greater milk production (P < .01) than UP as well as protein, fat, and solid yields. This response may be caused by a significant increase in feed intake for P diets. Use of a depletion period did increase precision of results but its use in practical feeding trials is controversial. Results in milk, milk protein, fat, and solid yields, and plasma urea were linear with protein level (L vs H). The second trial involved 44 multiparous cows averaging 114 d postpartum. Eight cows remained on a control (CON) diet of 11.7% CP while all others were randomly assigned in a 3 x 3 factorial in which dried (DBG) and wet brewers grains (WBG), and soybean meal (SBM) supplemented the CON to 14.8 (L), 16.3 (M), and 18.0% (H) CP. Diet composition varied in corn silage and ensiled ground-corn but alfalfa silage was constant on a dry matter basis. All diets were superior to CON in milk production and constituent yield. Brewers diets were superior to SBM for milk yield, protein, and solid yields. Part of this response may be related to superior intake for diets containing brewers and lower rumen ammonia and plasma urea. Cows receiving brewers diets have higher intakes than SBM and brewers appear to be utilized more efficiently. For mid-lactating cows an increase in milk at 18.0% CP resulted from brewers diets but not SBM. The H level resulted in a significant increase in milk yield and protein (kg) but also had the highest plasma urea and rumen ammonia level. / M.S.

Increasing the milking frequency of early lactation dairy cows increases their milk yield, both during increased milking and after the cows are returned to a normal twice-daily milking schedule. When milked four times a day (4X) for only the first twenty-one days of lactation, the right udder half produces 3 kg/d more milk than the left half, which is milked only two times a day (2X) over the course of lactation (Hale et al., 2003). Alterations to this increased milking frequency (IMF) approach have been investigated in order to maximize production of the animals and determine the most efficient practice for producers. The aim of this study was to determine the appropriate duration of early lactation IMF treatment by increasing milking frequency of early lactation cows for various lengths of time, and subsequently increasing the use of this management practice on Virginia dairy farms. The right udder half of twenty-three primiparous and multiparous Holstein cows were milked 4X for 10, 20, or 40 days at the beginning of lactation, and the left udder half 2X for the entire lactation. Udder-half milk yields were measured at various time points throughout lactation and used to calculate the difference between right (4X) and left (2X) udder halves. Overall, treatment did not have a significant effect on milk yield difference throughout the entire lactation; the udder half differences for each group were -0.45 kg, 1.92 kg and 4.62 kg for the 10 d, 20 d and 40 d treatments (P > 0.05). In addition to the IMF portion of the experiment, two different methodologies were used to investigate the possible mechanism of local regulation of milk yield in response to IMF treatment. Milk fatty acid analysis was performed on milk samples obtained from the above experiment. Three different groups of fatty acids were analyzed to detect potential changes in the right udder half (4X) when compared to the left (2X); the three groups were denovo, C16, and preformed fatty acids. There was no significant effect of treatment on fatty acid composition of right and left udder halves for any of the three groups (P > 0.05). The second methodology used to explore a possible mechanism behind increased milk yield following IMF treatment was immunohistochemistry of mammary gland tissue samples obtained after IMF treatment in a previous experiment. The key target investigated was a component of the Hippo signaling pathway, Yes-associated protein (YAP). Intensity of YAP staining in the cytoplasmic area of mammary epithelial cells (MEC) and number of YAP-positive stained nuclei located in the MEC were quantified for each of the images obtained. There was no effect of treatment or day on intensity of staining (P > 0.05) with no difference in the intensity of staining between 4X and 2X samples or d 21 and d 60 samples. However, the interaction for treatment x day tended to be significant (P < 0.06), with the d 60 samples tending to have higher intensity of staining than d 21 samples. For YAP-positive nuclei, there was a significant effect of day (P < 0.05), with d 60 samples having significantly more YAP positive nuclei. There was not a significant effect of treatment or treatment x day interaction (P > 0.05) with 2X and 4X samples having the same number of YAP positive nuclei. Results from the first experiment reveal that 40 d of IMF during early lactation is sufficient to produce an increase in milk and component yields throughout lactation. This practice could be implemented on Virginia dairy farms as a way to increase efficiency and milk yield per cow. Results from the second half of this research indicates that further research is needed to investigate the fatty acid content of milk from cows subject to IMF treatment during early lactation. In addition, YAP potentially plays a role in the changes occurring in the mammary gland, with increased intensity of YAP staining and increased number of YAP positive nuclei observed at 60 DIM. Understanding of this protein and its involvement in the mammary gland could lead to identifying a mechanism for which this increase in milk yield and components following IMF is occurring. Further research needs to be done to provide results supporting the current experiment. / MSLFS / The focus of this study is increasing milk yield by increasing milking frequency of early lactation cows. We will use a technique where each half of the cow's udder is milked with different milking frequencies. Previous studies have shown an increase in milk yield due to increased milking frequency. When milked four times a day for 21 days, the right udder half produced 2,032 lb. more milk than the left over the course of a lactation. This project will investigate modifications to the 21-day increase in milking frequency that might increase the use of this management practice on Virginia dairy farms. This experiment will determine the increase in milk yield when cows are milked four times a day for 10, 20, or 40 days. Farmers are concerned about return on investment - including time invested engaging extra milkings. This experiment will determine the effective duration of increased milking frequency needed to gain an increase in milk production with the minimum investment of time necessary to apply increased milking frequency - can the increase achieved with 20 days be achieved in only 10 or does increasing to 40 days provide an even greater benefit than 20-day application?

Titre de l'écran-titre (visionné le 27 novembre 2023) / Le sevrage est une étape cruciale dans l'élevage des chevrettes laitières. Une gestion inadéquate de cette phase peut entraîner non seulement des problèmes de morbidité et de mortalité, qui coûtent cher à l'éleveur, mais peut aussi avoir des répercussions défavorables sur la croissance corporelle et le développement de la glande mammaire des chèvres. L'objectif de cette recherche était d'examiner l'impact du moment de sevrage sur divers aspects tels que la croissance et la reproduction des chèvres, sur la production et la composition du lait et son rendement fromager, ainsi que sur l'expression des gènes impliqués dans le métabolisme protéique et lipidique de la glande mammaire. L'étude a été réalisée sur 40 chevrettes, qui ont été séparées de leur mère à la naissance et réparties en trois groupes selon le moment du sevrage (à 6, 8 et 10 semaines). Les résultats ont montré que les chevrettes sevrées tardivement (à 10 semaines) présentaient un poids significativement plus élevé que celles sevrées plus tôt (à 6 semaines), avec une différence moyenne de poids de 3 kg (P < 0,05) aux deuxième, troisième et quatrième mois, suite à quoi aucune différence significative n'a été notée et ce jusqu'à 200 jours de lactation (P > 0,10). Les chèvres ont en moyenne mis bas à l'âge de 373 jours, ont eu 1,60 chevreaux par chèvre, ceux-ci ayant un poids moyen de 4,17 kg par chevreau (P > 0,10). Concernant la production de lait, il a été observé que toutes les chèvres produisaient en moyenne 2,9 kg de lait par jour, indépendamment du moment du sevrage, et ce pendant les 200 jours de lactation (P > 0,10) et aussi pour les deuxième (3,95 kg par jour) et troisième lactations (4,66 kg par jour) (P > 0,10). Le moment du sevrage n'a pas eu d'impact sur la composition du lait en termes de matières grasses et de protéines. Aucune différence significative n'a non plus été observée quant la répartition des caséines, le profil des acides gras et le rendement fromager (P > 0,10). En revanche, l'étude a mis en évidence un effet significatif de la période de lactation sur ces paramètres. En particulier, une diminution de la teneur en matière grasse, des protéines, de la quantité de caséines et du rendement fromager a été observée au cours de la lactation, notamment aux jours 18, 45 et 100 (P < 0,01). L'étude de l'expression des gènes liés à la lactation de la lactation n'a pas révélé d'effet significatif du moment du sevrage sur l'expression des gènes liés au métabolisme protéique et lipidique de la glande mammaire (P > 0,10). Toutefois, elle a mis en évidence des corrélations significatives entre l'expression de certains gènes et le métabolisme des acides gras. La concentration en acides gras de novo a été positivement corrélée à l'expression des gènes FASN, ACACA, GPAM, G6PD, SREBF1 et PPARA (0,25 ≤ r ≤ 0,81; P < 0,01). D'autre part, la concentration en acides gras préformés dans le lait était positivement corrélée à l'expression des gènes LPL, FADS1, SCD1, CD36, FABP3 et PPARG (0,29 ≤ r ≤ 0,72; P < 0,01). Ces résultats soulignent l'importance de ces gènes dans la régulation de la composition de la matière grasse laitière chez la chèvre.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / A exposição materna à nicotina durante a lactação em ratos programa para hiperleptinemia e hipotireoidismo na prole adulta. Alterações nos níveis desses hormônios alteram o comportamento. Por isso, resolvemos investigar os efeitos comportamentais a curto e a longo prazo da programação neonatal pela nicotina em ratos Wistar. Foram implantadas minibombas em ratas lactantes contendo nicotina (NIC = 6mg/Kg/Dia) ou uma solução com uma concentração equivalente de solução salina (CON) do 2o dia ao 19o dia de vida pós natal. Sessenta e dois ratos NIC e 48 CON foram testados de acordo com o seguinte protocolo: 1) Em PN30 ou PN75 foram avaliados os níveis de ansiedade no labirinto em cruz elevado (LCE). Entradas em cada área do labirinto (braços abertos e fechados e centro) foram gravadas por um período de 10 minutos; 2) Uma hora após, os animais foram testados no campo vazado (CV) para analisarmos o comportamento de busca por novos estímulos. Os animais tinham 10 minutos para explorar o aparelho. O número de orifícios explorados foi anotado. 3) Em PN31-35 ou PN76-80 o animal foi submetido ao labirinto aquático radial de oito braços (LAROB) para avaliarmos a memória e o aprendizado. Cada animal foi testado 4 vezes por dia durante 5 dias consecutivos sendo a plataforma mantida no mesmo braço durante os 4 primeiros dias e trocada no quinto dia. Eles tinham 2 minutos para encontrar a plataforma de escape. A latência para encontrar a plataforma foi anotada. O percentual de tempo gasto no braço aberto no LCE para os animais NIC em PN30 (6,41,1 %) foi significativamente (ANOVA: P=0,024) menor que o grupo controle PN30 (9,91,4 %). O percentual de entradas no braço aberto foi significativamente menor (ANOVA: P=0,04) para os animais do grupo NIC em PN30 (32,42,9 %) quando comparados com o grupo controle PN30 (38,51,8 %). Não foi observada diferença (ANOVA: P>0,1) entre os grupos no número de entradas no braço fechado para as duas idades. Para o CV não houve diferença entre os grupos para as duas idades (ANOVA: P>0,1). No LAROB, os animais PN75 NIC (27424 s) tiveram uma diminuição significativa (ANOVA: P<0,006) na latência para encontrar a plataforma quando comparado ao grupo controle PN75 nos 4 primeiros dias (41045 s), não havendo diferença no 5o dia. Não houve diferença em PN30 (ANOVA:P>0,1). A programação neonatal pela nicotina resultou em um efeito a curto prazo no aumento dos níveis de ansiedade na adolescência. Não foi observada diferença no comportamento de busca por novos estímulos. Entretanto a programação neonatal por nicotina resultou em um efeito a longo prazo no comportamento-cognitivo observado pelo melhor desempenho na memória/aprendizado quando adulto. / Maternal nicotine exposure during lactation in rats rogrammes for hyperleptinemia and hypothyroidism in the adult offspring. Changes in the levels of these hormones are known to affect behavior. Hence, here we investigated the short- and long-term behavioral effects of neonatal nicotine exposure in Wistar rats. Lactating rats implanted with minipumps either containing nicotine (NIC=6mg/Kg/day) or a solution with equivalent concentration of saline (C) during the second postnatal day to the nineteenth postnatal (PN) days. Sixty two NIC and 48 C rats were tested according to the following protocol: 1) Either at PN30 or PN75, anxiety levels were assessed in elevated plus-maze (EPM). Entries into each area of the maze (open and closed arms and centre square) were recorded over a period of 10 min; 2) One hour, animals were tested in the hole board arena (HB) in order to assess novelty-seeking behavior. Animals were allowed 10 min to explore. The number of explored holes was noted; 3) Either at PN31 or PN76, learning/memory was assessed in the radial arm water maze (RAWM). Each animal was tested 4 times a day for 5 consecutive days. On the 5th day, the platform was moved to the arm located in the opposite side. They were allowed 2 min to find the hidden escape platform. The latency to find the platform was noted. The percentage of time spent in the open arms of the EPM by PN30 NIC animals (6.41.1 %) was significantly (ANOVA: P=0.024) lower than that of PN30 C ones (9.91.4 %). The percentage of entries into the open arms was also significantly lower (ANOVA: P<0.04) for PN30 NIC (32.42.9 %) animals when compared to that of PN30 C ones (38.51.8 %). No differences regarding these variables were observed between PN75 groups (ANOVA: P>0.1). No differences (ANOVA: P>0.1) were observed between groups regarding the number of closed arm entries at both ages. As for the HB test, no differences were observed between groups at both ages (ANOVA: P>0.1). In the RAWM, PN75 NIC animals (27424 s) displayed a significantly (ANOVA: P<0.006) reduced total (all trials summed) latency to find the platform when compared to PN75 C ones in the first four days (41045 s). No difference was observed regarding PN30 animals (ANOVA: P>0.1). Neonatal nicotine programming results in a short term effect on anxiety-like behavior, observed by a high anxiety levels during adolescence. No difference was observed regarding novelty-seeking behavior. However, neonatal nicotine programming causes a long-term late emerging effect on cognitive-behavior, observed by a better performance in learningmemory task at adulthood.