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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Influence of maternal feed allowance during mid-gestation on progeny muscle fibre development and sow performance over three consecutive cycles

Cerisuelo García, Alba 22 June 2007 (has links)
Es va realitzar un únic experiment amb una mostra inicial de 103 truges Landrace x Large White de genètica PIC, de entre 0 i 4 parts amb l'objectiu de determinar el efectes de l'alimentació de la truja gestant durant la part mitja de la gestació en el desenvolupament de les fibres musculars de la progènie y els rendiments productius de les mares. Aquestes truges van ser distribuïdes en dos grups experimentals, control (C, n = 49) i suplementat (S, n = 54). Les truges control van ser alimentades seguint el patró normal d'alimentació de la granja durant el període de gestació (2.5-3.0 kg/dia; 12.1 MJ EM/kg i 0.62 % de lisina de mitja). Les truges suplementades van rebre un suplement de +50% i +75% del mateix pinso, en el cas de truges nulípares i multípares respectivament, entre els dies 45 i 85 de gestació. Aquest mateix tractament es va aplicar durant tres cicles consecutius. Els garrins mascles (castrats) provinents dels cicles 1 i 3 es van dividir al naixement en dos grups (Control, C i Suplementat, S) segons el tractament nutricional rebut per les seves mares. Els rendiments productius d'aquests animals es van avaluar en les fases de transició (n = 958) i engreix (n = 636). Al sacrifici, diversos paràmetres de qualitat de la canal i de la carn (n=90) així com diferents característiques de les fibres musculars de la progènie (nombre total de fibres musculars, àrea mitja i tipus de fibres, n=70) varen ser estudiats. Els garrins nascuts de mares suplementades presentaren majors guanys de pes diaris i consums mitjos en el cicle 1 (P<0.05) i una superior eficiència de conversió en el cicle 3 (P<0.05) durant el període de transició, però aquestes diferències van desaparèixer a la fase d'engreix. Respecte als paràmetres de qualitat de la carn, els animals S presentaren un pH més elevat a les 24 hores després del sacrifici (pH24) en el múscul semimembranosus i una menor lluminositat (L*) mesurada en una secció transversal del múscul longissimus thoracis, en relació amb els porcs del grup C, de forma consistent en els cicles 1 i 3 (P<0.05). El tractament experimental també va provocar diferències en les característiques histològiques de les fibres musculars. Els garrins nascuts de mares suplementades van desenvolupar un menor nombre de fibres musculars però de major àrea mitja en ambdós cicles estudiats (P < 0.15), mentre que la relació entre el nombre de fibres secundàries i el nombre de fibres primàries es va mantenir constant entre tractaments. En l'animal adult, els porcs S presentaren un menor nombre de fibres tipus IIB (P<0.05) però amb una major àrea transversal (P<0.10) en relació als porcs C. Pel que fa a les truges, el pes viu (BW) i els nivells de reserves corporals [Gruix de greix dorsal (BF), profunditat de llom (LD) i nota de condició corporal (BCS)] van ser mesurats en diferents moments del cicle reproductiu en els tres cicles estudiats. La productivitat al moment del part i als 18 dies de lactació així com la longitud del interval deslletament-cobrició (WEI) varen ser enregistrats. Les truges que començaren l'experiment com a truges nulípares van ser capaces d'acumular teixit magre però també teixit lipídic en resposta a l'augment del nivell d'alimentació en gestació durant tres cicles consecutius, mentre que les truges multípares (>2 parts) dipositaren majoritàriament teixit gras. En termes productius, aquesta estratègia d'alimentació va resultar en un increment en el pes mig al naixement dels garrins nascuts de truges primípares en el cicle 3 (+300 g/garrí en el grup de truges S) però va tenir efectes negatius en quant a nombre de garrins deslletats en el grup de truges S. No es van trobar diferències en entre tractaments experimentals en el WEI. Un estudi exploratori de les dades del cicle 1 va demostrar que els nivells de reserves corporals al part (BW, BF i LD) estaven associats positivament amb les seves respectives pèrdues durant el període de lactació, però també positivament amb els seus nivells de reserves al deslletament. A més a més, es va trobar una associació dèbil però positiva entre la pèrdua de BF en lactació i el WEI (r=0.25, P<0.05). En aquest estudi, les truges primípares donaren lloc a garrins de menor pes al naixement i al deslletament i a WEIs més llargs en comparació amb aquells de les truges multípares (P<0.05). Finalment, la nota de condició corporal visual (BCS) va presentar una associació moderada (r=0.54-0.49, P<0.01) amb el nivell de reserves corporals de la truja mesurats mitjançant ultrasons (BF i LD). En resum, un increment del nivell d'alimentació en la part central de la gestació va provocar un efecte en les característiques de les fibres musculars i la qualitat de la carn de la progènie, sense afectar als rendiments productius. A més a més, aquesta estratègia d'alimentació va presentar efectes beneficiosos en el pes dels garrins al naixement en les truges de primer part, però no en truges multípares. / In order to study the effects of pregnant sow nutrition on progeny muscle fibres development and sow performance, a study involving an initial pool of 103 Landrace x Large White PIC sows from 0 to 4 parities was designed. Sows were divided into two experimental groups, control (C, n=49) and supplemented (S, n=54). Control sows were fed according to the feeding strategy routinely followed on the farm throughout gestation (2.5 to 3.0 kg/day; 12.1 MJ ME/kg and 0.62 %lysine). Supplemented sows were provided with an extra feed allowance of +50% and +75% of the same feed for both gilts and multiparous sows, respectively, from day 45 to day 85 of gestation. The same feeding strategy was applied over three consecutive reproductive cycles. Male (castrated) progeny from cycles 1 and 3 were assigned at birth to one of the two treatments (Control, C and Supplemented, S) according to the dietary treatment received by their mothers. Growth performance throughout the nursery (n=958) and growing-finishing periods (n=636) was evaluated. Additionally, carcass and meat quality traits (n=90) and muscle fibre characteristics (total number of muscle fibres, mean cross-sectional area and fibre types, n=70) were studied at slaughter. Pigs born from supplemented mothers showed higher daily weight gains and feed consumption rates in cycle 1 (P<0.05) and higher feed efficiencies in cycle 3 (P<0.05) during the nursery period, but these differences disappeared in the growing-finishing phase. Regarding meat quality, S pigs showed a higher ultimate pHs (pH24h) in the semimembranosus muscle and a lower lightness (L*) in the cross-section of longissimus thoracis muscle compared to the C group of pigs, consistently in cycles 1 and 3 (P<0.05). Differences in muscle fibre characteristics were also found between treatment groups. The S pigs showed a lower number of muscle fibres with higher mean areas in both cycles (P<0.15), and an invariable estimated secondary to primary fibres ratio. In the adult animal, S pigs showed a lower number of type IIB fibres (P<0.05), but with larger sizes (P<0.10, cross-sectional area) compared to C pigs. Regarding sows, body weight (BW) and body reserves [backfat (BF), loin depth (LD) and body condition score (BCS)] were measured at different times throughout the reproductive cycle over the three cycles studied. Productive performance at farrowing and on day 18 of lactation and weaning to oestrus interval (WEI) were also recorded. Sows which started the study in their first parity accumulated both, lean and fat tissue in response to the increased gestation feed allowance over the three cycles, while multiparous sows (>2 parities) mainly accreted fat tissue. Additionally, the extra feeding enhanced primiparous piglet weight at birth in cycle 3 (+300 g/pig in the S group of sows) but impaired lactation performance in terms of weaned pigs in the S group of sows. No differences were found between treatments regarding WEI. An exploratory study in the sows of cycle 1 revealed that body reserves levels at farrowing (BW, BF and LD) were positively associated with their respective losses during the lactation period, but also with their levels at weaning. Additionally, BF losses during lactation showed a low but positive association with WEI (r = 0.25, P<0.05). Also, in this study, first parity sows showed lower piglet weights at farrowing and at weaning and larger WEIs compared to multiparous sows (P<0.05). Finally, the visual body condition score (BCS) appeared to be moderately correlated (r=0.54-0.49, P<0.01) with sow body reserves measured by ultrasounds (BF and LD). Overall, an extra feed allowance during mid-pregnancy affected progeny muscle fibre characteristics and meat quality traits without leading to differences in growth performance. Moreover, this feeding strategy had beneficial effects on piglet birth weight in first parity sows, but not in multiparous sows.
2

Stressed Out and Fed Up: The Effect of Stress on Maternal Feeding Behaviors and the Moderating Role of Executive Functioning

Mendiola, Isabel 01 January 2018 (has links)
Stress is associated with a range of unhealthy eating habits. However, no previous studies have used experimental design to take an intergenerational perspective in the examination of how stress may influence parental feeding behavior, nor have they examined potential protective factors. The current study tests the effects of stress on maternal feeding behaviors and explores the potential protective role of maternal executive functioning (EF). We manipulated maternal stress with the Trier Social Stress Task (TSST) in a community sample mothers (N = 61, Mage = 33.45 years). We measured maternal EF with a series of computerized tasks. Maternal feeding behavior was observationally coded using standardized procedures. Results indicate a main effect of stress on controlling feeding styles. Furthermore, this effect of stress on controlling feeding behaviors is ameliorated among mothers with higher levels of EF. Results suggest potential factors to be considered in the treatment and prevention of diet-related illnesses.
3

Child Temperament and Parenting Style as Contributors to Maternal Feeding Practices

Carroll, Vincent A., Dalton, William T., III, Dixon, Wallace E., Jr. 01 February 2012 (has links)
No description available.
4

Exploring the Relationships Between Mothers' Use of Food to Soothe, Feeding Type and Mode, Maternal Feeding Style, Infant Behavior, and Infant Weight-Related Outcomes During Early Infancy

Hupp, Megan K 01 August 2020 (has links) (PDF)
Rapid infant weight gain (RWG) in the first six months postpartum is a strong predictor for obesity during childhood and adolescence. Although biological factors can influence infant weight gain trajectories, the modifiable factor of parent feeding practices can also have an influence. The use of food to soothe (FTS), or the act of feeding a child when he/she is upset for reasons other than hunger, has been associated with unhealthy eating behaviors and less-favorable weight outcomes in children and older infants. However, limited studies have explored the use of FTS during early infancy before the introduction of solids foods. The present study was a secondary analysis of mothers who completed previous infant feeding studies (n = 134) and was aimed at exploring whether maternal-reported use of FTS was associated with greater infant weight gain during the first six months postpartum and whether feeding type (exclusive breastfeeding versus exclusive formula-feeding versus mixed feeding) or bottle-feeding intensity (percent of daily feedings from a bottle) moderated this association. Both maternal-reported and observational measures of maternal and infant characteristics and their associations with the use of FTS were also explored. Individual correlations as well as multiple and logistic regressions were used to assess whether FTS predicted change in weight-for-age, weight-for-length, and/or RWG from birth to study entry. One-way ANOVA tests were used to assess the differences in use of FTS by feeding type and/or bottle-feeding intensity. Individual correlations and multiple regressions were used to assess whether maternal feeding style and/or infant temperament, clarity of cues, and/or eating behavior predicted the use of FTS. The mean age for infants was 14.8 weeks (SD = 7.1, range = 1.7 - 31.0 weeks). The results showed that the use of FTS had a significant negative association with percent of daily feedings from a bottle (r = -0.20, p = 0.021), and a significantly higher association among mothers who reported mixed feeding (M = 2.87, SD = 0.20) versus exclusive formula feeding (M = 2.20, SD = 0.20). Greater pressuring feeding, greater infant negativity, and lower infant surgency were all significant predictors for the use of FTS (p < 0.05). FTS was not significantly associated with infant weight gain during the first 6 months postpartum. Neither feeding type or bottle-feeding intensity moderated the relationship between the use of FTS and infant weight gain. Future studies would benefit from recruiting a more diverse sample population, including measures of FTS that have been validated on infants younger than 3 months, and following the infants at more frequent time points from birth to 6 months postpartum.

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