The suitability of diminishing return functions such as the monomolecular and rectangular hyperbola equations, specifically re-parameterized for analysing energy balance data, has been investigated in ruminants, pigs, broilers and turkeys. In the current study, these equations were applied to a total of six time course profiles with male and female broiler breeder pullets (Ross 308 between 1 and 21 weeks of age, n=63 for each sex) in order to provide estimates for energy and protein requirements for maintenance and growth. Non-linear regression was used to estimate parameters and combine them to determine other biological indicators. All statistical computations were implemented in SAS (SAS 2000) by means of the NLMIXED procedure. The best-performing model was identified based on model behaviour when fitting the data, biologically meaningful parameter estimates and statistical performance. In spite of similarity between the biological indicators calculated for each sex using parameter estimates of the two models, quantitative examination of their predictive ability by error measurement indices showed the monomolecular model was superior. The metabolizable energy (ME) and crude protein (CP) requirements for maintenance ranged from 365 to 432 kJ/kg live weight (LW)/d and from 4·3 to 4·9 g/kg LW/d, respectively. The average ME and CP utilization ranged from 11·30 to 12·10 kJ/g body weight (BW) gain and from 0·61 to 0·64 g/g CP intake, respectively. The results obtained using the models were within the range reported by different researchers. Utilization of ME and CP for gain was more efficient at low levels of energy and protein intake, and gradually decreased as the level of energy and protein intakes increased. In conclusion, the models described herein were considered advantageous because they could predict the magnitude and direction of the responses of growing broiler breeder pullets to dietary ME and CP intake, which can be used in choosing and developing special feeding programs to decrease production costs.

Globally, agriculture accounts for 0·80–0·90 of all freshwater used by humans and, in many crop production systems, this water use is unsustainable. The current paper focuses on the potential exploitation of novel drought stress biology in both crop improvement programmes and via changed crop management practices. The aim is to deliver ‘more crop per drop’. In order to respond to the challenge of feeding a world population of seven billion and growing, it is concluded that an interdisciplinary approach is needed involving new genetic opportunities and plant breeding. It is also shown how crop management can exploit the drought stress physiology of plants to deliver improved water productivity without sacrificing crop yield.

Réunion Island, situated in the Indian Ocean, presents a unique case study for modelling regional bio-economic parameters of the dairy industry. It is a good example of a closed system for several parameters of the model such as movement of animals, labour, consumption and available land. The existence of several agro-ecological zones from tropical to temperate, and various different types of terrain and vegetation presents another unique opportunity to study the impact of these features on the dairy industry. The present study models the dairy sector at a regional (island) level to study the impact of new or adapted agricultural policies in relation to changes in subsidy levels, price fluctuations and environmental policies (mainly nitrogen management). The model can be used to generate a number of scenarios to explore the effects of various policy measures, such as fixing the stocking rate according to EU norms, increasing or decreasing the milk subsidy, intensification (such as an increase in milk production to the allotted quota of 40 million litres/yr) and varying labour/price constraints (such as a reduction in labour hours or an increase or decrease in the milk price). The model is being utilized by the local dairy cooperative as a discussion support tool to study the implications at the regional scale of expanding the sector and assessing its economic, environmental and social impact.

The coding region of the alpaca Agouti signalling protein (ASIP) gene was sequenced. It was determined to be 402 nucleotides long and code for a protein that is 133 amino acids long. Eight mutations were identified in a sample of 15 alpaca, five in the coding region and three in the introns flanking the exons. In silico analysis showed that three of the five mutations in the coding sequence, c.325_381del57, c.292C>T and c.353G>A are probable loss-of-function mutations. The three mutations were strongly associated with black fibre colour, with 0·90 of black alpacas in the current study having two copies of one or another of the mutations. However, not all black animals displayed the putative ‘aa’ genotype, and almost half of the non-black animals did display that genotype. Contributing factors such as regulatory region mutations, interactions of ASIP with melanocortin-1 receptor (MC1R) and α-melanocyte stimulating hormone (α-MSH), the effect of dilution genes and subjective phenotype assignment are discussed. These mutations will allow alpaca breeders to select for or against black, but they do not explain all black phenotypes in this species.

Aquaculture development over the past 50 years has been facilitated largely by the application of science and the introduction of new technologies. Although aquaculture is a very diverse sector in products, production systems and business structures, almost every activity has benefited from scientific advances. However, the impact of technological progress is most clearly seen where there has also been substantial industrial consolidation. This has provided greater capital resources for investment and a more attractive market for suppliers of innovations to target. It has also encouraged consolidation of research capacity and stronger articulation between private and publicly funded research efforts. Further development along current trajectories is possible through advances in genomics, information technology, materials science and other areas. However, there may also be substantial disruptions if, for instance, energy becomes much more expensive, or large mono-cultures are impacted by climate change. Substantial change could also be driven by policies that aim at bringing realistic external costs of environmental services into company accounts. Research into more resilient aquaculture systems that comply more with ecological than financial accounting principles is under way, but will require substantial development to meet the challenges of rising food needs and social aspirations.

Global aquaculture production continues to grow rapidly yet a small proportion of the animals and plants being used come from managed breeding and improvement programmes. The biology of aquatic organisms offer many opportunities for rapid genetic gains as new genetic and genomic techniques make the management of improvement programmes feasible in a wider range of species. The current paper describes the application of a wide range of techniques, many unique to aquatic organisms, and their potential to secure aquaculture production in the future.

The current paper briefly summarizes the available evidence regarding the potential of urban agriculture to respond to a number of key urban challenges and reviews the perspectives on urban agriculture applied by local and national authorities. The last section of the paper briefly presents the authors’ views on the development of urban agriculture as an integral part of sustainable city development.