(ShareCast News) - Full-year underlying pre-tax profits at supermarket giant J Sainsbury are expected to be moderately ahead of its £548m forecast, the company said on Wednesday.In a second quarter trading statement, the company said total retail sales for the period were up 0.3% excluding fuel sales, and down 1.8% if petrol was included.Like-for-like retail sales fell 1.1 per cent excluding fuel and were 3.3% lower including petrol."During the quarter we saw an improvement in our key trading metrics. Both volume and transactions grew as the decline in average basket spend in supermarkets continued to stabilise. Whilst the market is clearly still challenging, with food deflation impacting many categories, we are making good progress on delivering our strategy," said chief executive Mike Coupe.