Tryptophan requirement of first-cycle commercial laying hens in peak egg production

An experiment was conducted to evaluate the digestible tryptophan (Trp) requirement of laying hens from 22 to 34 wk of age. A total of 252 Hy-line W-36 laying hens were selected at 16 wk of age and allocated by weight (P = 0.90) to 7 dietary treatments resulting in 12 replicate cages of 3 birds for each treatment. A Trp-deficient basal diet was formulated using corn, corn gluten meal, and soybean meal for each of the 3 dietary phases and supplemented with synthetic L-Trp to provide 105, 119, 133, 147, 162, 176, and 190 mg digestible Trp on a daily basis over the experimental period. To adapt the hens to experimental diets, pullets were fed complete diets that contained increasing amounts of corn gluten meal. Hens received a controlled amount of feed daily based on feed intake expected under commercial conditions. Linear and quadratic broken-line, and quadratic polynomial models were used to estimate digestible Trp requirements based on hen-housed egg production (HHEP), egg mass (EM), and feed efficiency (FE). FE was calculated using EM and feed intake. Digestible Trp requirements were estimated to be 137, 183, and 192 mg/d for HHEP; 133, 180, and 183 for EM and 133, 177, and 173 for FE using linear broken-line, quadratic broken-line, and quadratic polynomial analysis, respectively. The quadratic broken line model in this experiment resulted in the best fit (R²) for all parameters measured. Linear broken line estimates resulted in lower estimates that the other models, and HHEP resulted in higher estimated digestible Trp requirement than EM and FE.

Estimating resources for setting up an HV service for postnatal depression

Postnatal depression (PND) presents a significant health burden for mothers and their offspring. Research has indicated that screening for PND increases detection (Holden et al, 1989) and also that counselling by health visitors (HVs) is an effective intervention. This article describes a pilot PND screening and treatment project which aimed to assess the resource and organizational implications of introducing new health visiting services modelled on research findings compared with existing practice. The pilot project included approximately 400 new mothers in an inner city multicultural area and confirmed previous findings regarding prevalence of PND (19%) and the effectiveness of brief counselling interventions. It resulted in significantly reduced estimates of the HV resources that would be required to introduce screening as part of the core health-visiting programme. The project also revised expected training requirements and challenged existing concerns about its appropriateness for minority cultural groups.